LIBRAR Y

FEBE- Î961

U. s. DtPÁ¡<,,>^iMl OF AGidCÜLl-yí THE

MOSQUITOES

OF

ALASKA

JRD

Agriculture Handbook No. 182

Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE

U

<
The purpose of this handbook is to present information on the biology, distribution, identification, and control of the species of mosquitoes known to occur in

Alaska. Much of this information has been published in short papers in various

journals and is not readily available to those who need a comprehensive treatise on

this subject ; some of the material has not been published before. The information

l)r()UKlit together here will serve as a guide for individuals and communities that

have an interest and responsibility in mosquito problems in Alaska. In addition,

the military services will have considerable use for this publication at their various

installations in Alaska.

CuUseta alaskaensis, one of the large

"snow mosquitoes" that overwinter

as adults and emerge from hibernation while much of the winter

snow is on the ground. In some

localities this species is suJBBciently

abundant to cause serious annoyance.
THE

MOSQUITOES

OF ALASKA

By C. M. GJULLIN, R. I. SAILER, ALAN STONE, and B. V. TRAVIS

Agriculture Handbook No. 182

Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE

Washington, D.C. Issued January 1961

For «ale by the Superintendent of Document«. U.S. Government Printing Office

Washington 25, D.C. - Price 45 cent»
Contents

History of mosquito abundance

and control

Mosquito literature

Economic losses

Mosquito-control organizations

Life history

Eggs_".

Larvae

Pupae

Adults

Distribution

Abundance

Predicting abundance

Effects of weather on mosquito activity

Biology

Larval habitats

Habitat preferences and

relative economic importance of species

Water temperature of

larval habitats

Adult food habits

Longevity

Flight range

Mating

n

Page

1

3

4

5

5

6

6

6

6

7

11

12

14

16

16

21

22

23

23

23

24

Page

Biology—Continued

Oviposition 25

Hibernation 25

Surveys of the mosquito problem. 25

Mosquito surveys 25

Engineering surveys 29

Methods of mosquito control 29

Control of larvae 30

Environmental control-., 30

Control with insecticides. 31

Protection against adults 32

Personal protection 33

Insecticides 34

Control of resistant mosquitoes 39

Technique for mosquito collection

and survey 39

Identification of species 42

Keys and notes for identification. 42

Genus Aedes Meigen 45

Genus Culiseta Felt 71

Genus Anopheles Meigen 77

Genus Culex Linnaeus 79

Literature cited 81

Appendix 87
THE MOSQUITOES OF ALASKA

By C. M. GJULLIN, R. I. SAILER. ALAN STONE, and B. V. TRAVIS.^ entomologists,

Entomology Research Division, Agricultural Research Service

History of Mosquito Abundance and Control

The mosquito problem in Alaska

seems to have changed very little

since it was first recorded by early

travelers and explorers. The first

reconnaissance of Alaska after its

purchase from Russia in 1867 was

made by Raymond (94.) ^ of the

U.S. Army Engineer Corps in 1869.

During his voyage up the Yukon

River by steamboat, mosquitoes

were present in large numbers. He

wrote :

The swarms of mosquitoes and gnats

which abound on the river during the

months of June and July proved a very

serious annoyance. When the boat was

not in motion, we were obliged to wear

face nets and gloves; and on one occasion an attempt to make sextant observations failed completely from this

cause. The mosquitoes are much larger

than those met with in lower latitudes.

Petrof (89), while investigating

the population and resources of

Alaska m 1880, found mosquitoes to

be a severe annoyance in the lower

Kuskokwim Valley. He wrote :

There is another feature in this country which, though insignificant on paper, is to the traveler the most terrible

and poignant infliction he can be called

upon to bear in a new land. I refer to

the clouds of bloodthirsty mosquitoes, accompanied by a vindictive ally in the

shape of a small poisonous black fly,

under the stress of whose persecution the

strongest man with the firmest will must

either feel depressed or succumb to low

' Now with the Department of Entomology, Cornell University, Ithaca, N.T.

' Italic numbers in parentheses refer to

Literature Cited, p. 81.

fever. . . . The traveler who exposes his

bare eyes or face here loses his natural

appearance; his eyelids swell up and

close, and his face becomes one mass of

lumps and fiery pimples. Mosquitoes

torture the Indian dogs to death, especially if one of these animals, by mange

or otherwise, loses an inconsiderable

portion of its thick hairy covering, and

even drive the bear and the deer into

the water.

During a military reconnaissance

of the Copper River Valley in 1898

under the direction of Abenjrombie

(i), captain of the Second U.S.

Infantry, a party led by Rafferty

(91) investigated the route from

Valdez to Copper Center on the

Klutina River. His party camped

for several days at Copper Center.

He described the mosquito situation

at that time (June 9-13) as follows :

The long-expected pests, the mosquitoes, were out in full force during the

stay at this camp, and the men were compelled to wear veils day and night, with

gloves to protect the hands. The ferocity of these mosquitoes I regard as something remarkable. The species found

here is not the large, singing sort seen

in the States, but a small, silent, business-like insect, sharp of bill, who touches

the tender spot in a surprisingly short

time after alighting. After making their

~ appearance they never left the expedition for a day.

The conditions described by these

early travelers do not prevail in all

parts of Alaska with equal intensity, nor are they always as severe

in the same locality from year to

year. However, Stefansson (JOl)

after many years of travel and ex-
AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

ploration in the North considered

mosquitoes one of the principal obstacles to the development of this

region.

The first information on the species of mosquitoes that are such a

severe pest in many places in Alaska

may have been obtained by Trevor

Kincaid (Coquillett i?(9) of theHarriman Alaska Expedition in 1899.

He collected large numbers of insects, including two species of mosquitoes. Mosquito collections have

also been made by J. S. Hine of the

National Geographic's Mount Katmai expedition in 1917, as well as

by H. G. Dyar in 1917 and J. M.

Aldrich in 1921.

The habits, biology, and methods

of control of mosquitoes in Alaska

were first investigated in the summer of 1931 in a cooperative project

between the U.S. Bureau of Entomology and the U.S. Smelting and

Mining Co. The investigations

were carried on by Tidloch {106)

at Fairbanks, Alaska. Fifteen

species were collected in the area

during the summer. Recommendations for control of mosquitoes affecting the men employed in golddredging operations there included

burning of the dead vegetation to

facilitate evaporation of partially

covered pools, minor drainage, and

spraying of breeding areas adjacent to the mining operations with

diesel oil.

Additional information on the

distribution, abundance, and species

of mosquitoes in Alaska was obtained by Stage in 1943 {99).

Chamberlin also added considerable

infomiation to our knowledge of

Culicidae during 1943-Í5 {99).

During 1956 in northeastern Alaska

Ehrlich {9a) collected several species of mosquitoes not previously

reported from beyond the tree line.

Studies of the biology and control

of arctic mosquitoes were made for

the U.S. Navy installations at

TTmiat. Alaska, by Jachowski and

Schultz {75) and by Knight {80)

during 1947-48. Work in this area

was carried on mainly during the

summer and was handicapped by

huge swanns of mosquitoes, which

emerged after the spring thaw and

persisted until the first frost. Four

species wei-e present. Neither fuel

oil alone nor fuel oil and DDT

gave satisfactory control in airplane applications against larvae,

but DDT-fuel oil applications

against adults markedly reduced

the mosquito population for a few

days.

The need for protective measures

against the hordes of biting insects

in the arctic and subarctic became

more urgent with the increased military interest in these regions after

1941. As a result of a discussion

of these problems by workers in the

U.S. Department of Agriculture

and the office of the Surgeon General, U.S. Department of the Army,

a project was outlined by the former to obtain basic information for

insect control. This project was

approved by the Surgeon General

in 1946, and the Department of

Agriculture was designated as the

resjoonsible agency. Specialists

were assigned from the various

agencies concerned. Quarters and

subsistence for the men and all supplies and equipment were furnished

by the military except microscopes

and a limited amount of similar

equipment, which were provided by

the Department of Agriculture.

An advance party of five arrived

in Alaska on May 4, 1947. In all,

21 persons were employed on the

project during 1947, and the number was increased to 40 during 1948.

U.S. Air Force pilots were assigned

as needed, and 19 enlisted men were

attached to the project for varying

periods during the summer. In

1949, 10 men carried on the work;

pilots and several enlisted men were

again assigned as needed. In 1950

the party was limited to six men, in

addition to the plane pilots and

four enlisted men.
THE MOSQUITOES OF ALASKA

The U.S. Public Health Service,

which assigned several men to the

project in 194:8-49, has since maintained a permanent staff of three

entomologists on mosquito and

black fly problems in Alaska.

The personnel carrying on these

investigations from 1947 through

1950 were principally entomologists, but climatologists, botanists,

an aquatic biologist, and an equipment engineer were also included.

The major effort was directed

against mosquitoes, which are the

most widely dispersed and troublesome pests in Alaska, but much time

was also devoted to black flies.

Most of these studies were carried

on in May, June, and July, but during 1948 the work on some phases

was begun in March and continued

through September.

The work on mosquitoes was directed toward determining what

species were present, which were the

most important as pests, where they

bred, and what could be done toward their control. To obtain this

information, detailed biological

studies were made of the mosquito

fauna, reared specimens were collected for taxonomic purposes, and

experiments were conducted on the

control of mosquitoes with ground

and aerial equipment. The effectiveness of standard repellents

against Alaskan mosquitoes was

also determined.

The effect on mosquito larvae of

DDT residues, which were left

when larvae and adults were

sprayed in previous years, was investigated in 1950. Further investigations of the effects of the

residues Avere made by entomologists and other scientists from the

offices of the Quartermaster General

and the Surgeon General, U.S. Department of the Army, in 1951.

This group also investigated the effectiveness and acceptability of

clothing treated with insect repellents and the effectiveness of insecticidal fog-producing equipment.

The relationship of weather to

mosquito abundance was also

studied in Alaska by R. I. Sailer

of the XT.S. Bureau of Entomology

and Plant Quarantine from 1951 to

1953.

Mosquito Literature

The amount of literature on mosquitoes has become exceedingly

large. Each year about a thousand

references to various phases of the

biology of mosquitoes and the diseases they carry appear in widely

scattered publications. Probably

no other group of insects has received so much study throughout

the world. Some of the publications of especial interest to workers

concerned with the mosquitoes of

Alaska are given at the end of this

handbook.

One of the early comprehensive

books on the mosquitoes of the

Americas was published by Dyar

{27) in 1928. It deals with the distribution, biology, and taxonomy of

mosquitoes on these two continents.

Matheson's handbook {86), revised in 1944, gives much information on the taxonomy and biology

of the mosquitoes of North America, and it includes a discussion of

their relation to human welfare and

problems of control.

In 1948 Natvig {87) published

an authoritative book on the biology, distribution, and taxonomy of

the Danish and Fennoscandian mosquitoes. A number of the species

of northern Europe also occur in

In 1949 Bates {10) compiled

voluminous facts on the biology and disease relationships of

mosquitoes.

The taxonomy, biology, distribution, and medical importance of
AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

North American mosc[uitoes are

covered in an authoritative book by

Carpenter and LaCasse {18), which

appeared in 1955.

In 1959 Stone, Knight, and

Starcke {]0'2a) pubhshed a synoptic catalog on the mosquitoes of the

world. This is a useful source of

information on the synonymy and

the world distribution of the species found in Alaska.

A textbook by Herms and Gray

{63) is designed primarily for entomologists, engineers, and staff

employees who are directing the

activities of mosquito-abatement

districts. It gives information on

laws and agencies for mosquito

abatement, education of the public,

general principles of abatement

methods and techniques, abatement

of disease vectors, and a host of

related data.

The following periodicals will be

of interest to students of Culicidae :

Mosquito News, published quarterly

by the American Mosquito Control

Association at Albany, N.Y., and

the Proceedings, published each

year by the New Jersey Mosquito

Extermination Association, the California Mosquito Control Association, the Florida Anti-Mosquito

Association, and the Utah Mosquito

Abatement Association. Articles

on mosquitoes also appear in bulletins and reports of the U.S. Public

Health Service and in various entomological, medical, and other scientific journals throughout the world.

Economic Losses

Mosquito species found in Alaska vere annoyance they cause are imare not known to cause disease, portant economic deterrents to the

However, the huge numbers (fig. 1) development and progress of the

present in many places and the se- State. The efficiency of all human

PN-808

FIGURE 1.—Mosquitoes resting ou a man's back—typical of the mosquito problem

that in some years may affect much of Alaska during June and July.
THE MOSQUITOES OF ALASKA

effort in any area where large numbers are present is greatly reduced

by the necessity for "fighting them

off" or for using bed nets, head

nets, and other protective clothing.

Losses in weight and milk production of livestock, as well as the adverse effect on wild game, occur

when large numbers of these pests

are present. Alaska, also loses

much of its recreational value because of mosquitoes, and consequently the tourist trade is adversely affected.

Mosquito-Control Organizations

Mosquito-control operations in

Alaska in recent years have been

carried on almost exclusively by the

military for the protection of their

personnel. However, agricultural

areas and many small centers of

population are not included in these

control operations. As the State

develops and the population increases, control agencies to handle such local problems will be

necessary.

Local mosquito-control agencies

are commonly called mosquitoabatement districts. Laws have

been enacted to facilitate the organization of such districts. These

laws vary considerably in the different States, but the most common is

one whereby a district may be organized upon the petition of 5 or

10 percent of the legal voters of the

area affected. After a public hearing, the board of trustees of the

county in which the area is situated

decides whether in the public interest a district should be formed, and

if it so determines, it fixes the

boundaries of the district. The district is governed by a board of trustees, whose members serve without

pay. The board manages the affairs of the district, employs personnel, and determines the annual

budget. The county board of supervisors levies a special tax to raise

the funds required for this budget.

Mosquito-abatement districts in

many States with different types of

laws or without laws are organized

under county or city supervision or

under the direction of county health

departments (see Herms and Gray

63).

In 1951 there were mosquitocontrol associations in New Jersey,

Florida, California, Virginia,

Utah, and Illinois (Stage 98).

Since then one has been formed in

Oregon and one in the Northeastem States. Each of these associations holds annual meetings,

and most of them publish their proceedings, which contain valuable

contributions on mosquito biology

and control.

There is also the American Mosquito Control Association, which is

international in scope and has over

1,200 members. It is a nonprofit

professional association composed

of entomologists, sanitary engineers, control officials, medical personnel, and laymen, who are charged

with or are interested in mosquito

control and related work. Annual

meetings are held in various parts

of the United States, usually conjointly with those of the State

associations.

Life History

Mosquitoes have diverse breeding

habits, particularly in regard to the

type of place they lay their eggs,

but all have one characteristic in

common—they live part of their

life in water and water only. It

may be in a small tin can or in a

vast tidal marsh.

Some species may be found in

several kinds of water and others
AGR. HANDBOOK 18 2, U.S. DEPT. OF AGRICULTURE

only in restricted areas in certain

types of breeding places. For example, Aedes ßavescens is found

only in unshaded flood plains,

whereas many of the Alaskan Aedes

species are found in a considerable

range of open and semiwooded

breeding places. Some genera such

as Aedes lay their eggs on ground

that may later be flooded, whereas

others such as Culex and Culiseta

lay them directly on the water

surface.

Temperatures of air and water,

alkalinity or acidity of the water,

and associated shelter and vegetation affect the abundance and presence of most species. The species

also differ in biting habits, longevity, and flight range.

The mosquito has a complete

metamorphosis. There are four

well-defined stages—the egg; the

larva, sometimes called wiggler ; the

pupa, or tumbler; and the adult, or

imago.

EGGS

The eggs may be laid singly as

with the anophelines, in rafts as

with Cidex and Cidiseta, or in scattered groups of various numbers as

with Aedes. In very warm weather the eggs of some species may

hatch within 2 or 3 days after they

are laid. However, in northern

latitudes the eggs laid by Aedes in

the late summer do not hatch until

flooded the following spring. If

not flooded the first season, they

may remain viable for several years

(Gjullin et al. 58). There is still

some question as to whether northem Aedes eggs require a certain

amount of drying and exposure to

cold before they hatch or, as we believe, a low oxygen concentration

(Gjullin et al. 61). A blood meal

is considered necessary for the production of viable eggs, but exceptions have occurred both in the

g&nws, Aedes (Hocking ö5) and Cwhx (Wray 115).

LARVAE

All mosquitoes spend their larval

and pupal stages in water, and

most of them move freely about as

aquatic insects. Without water

these stages cannot survive for more

than a few hours. The larvae of

most species must come to the water surface for air, which they obtain through an air tube or other

appendage located at the end of the

"tail." The larvae shed their skins

four times. The larval stage

usually lasts from 4 days to 2 weeks,

but some Aedes mosquitoes may remain as larvae for a month or more

when the water temperature is just

above freezing.

The food of mosquito larvae consists of microscopic plants and animals and organic debris. Some

species prey on the larvae of other

species, and some are cannibalistic.

Barber (9) has reared larvae on

pure cultures of various organisms,

and Hinman (6^) has suggested

that materials in solution or colloidal suspension in the breeding

water form a part of the larval food.

We have reared several species of

Aedes and Cnlex in the laboratory

on ground dog food and blood albumin and also on yeast and powdered milk.

PUPAE

With the fourth larval molt the

pupal stage appears. The pupae

move about by somersaulting.

Their life is short and active. An

excellent account of the emergence

of an adult mosquito from the pupal

stage is given by Marshall {SJi).

ADULTS

Only the female mosquito has

mouth parts adapted for bloodsucking. While the insect is biting, it

injects a secretion that causes itching.
THE MOSQUITOES OF ALASKA

Cvlex territans feeds only on

cold-blooded animals such as snakes

and frogs. There are no records of

Cidiseta niorsitan.s biting man. All

the other true mosquitoes in Alaska

feed on wami-blooded animals.

Many of these species also feed on

plant nectars.

The food of male mosquitoes consists of nectars and other plant

juices, but not blood. In the laboratory we have kept alive both

sexes of some species for long periods on raisins, fruit juices, and

sugar solutions.

Distribution

Despite the undisputed severity

of the mosquito problem in Alaska,

the problem is not of equal severity

in all localities or in the same locality from one year to another.

Like all animals and plants, the

distribution of the various mosquito

species over an accessible area is determined by the suitability of the

environment. Where marked differences of climate and topography

prevail, it is to be expected that

some species will thrive in one part

and be reduced in number or entirely absent in another. Knowledge of these factors and how they

function is necessary if the mosquito ¡problem is to be handled intelligently.

In discussing the relative abundance and distribution of mosquitoes in different parts of Alaska,

it is convenient to divide the State

into four zones, which coincide with

biotic provinces or Alaskan extensions of such provinces described by

Dice (36) in 1943. These zones are

shown in figure 2 and are defined

as follows:

(1) Sitkan.—This zone includes that

part of the Pacific mountain region from

Cook Inlet to the southern tip of the

Panhandle. It is a narrow strip of

mountainous coast (fig. 3) with numerous' adjacent island.s. The mountains

rise from .5,000 to 9.000 feet. Great glaciers fall from the mountains and often

debouch directly into the sea. The climate is mild and over most of the Panhandle not greatly different from that of

the Puget Sound area. Rainfall is high

with an annual average in the extreme

southeast of as much as 160 inches.

Sitka spruce and western hemlock predominate in the forests.

The Cook Inlet area is an extension of

the Sitkan zone but is in many respects

intermediate between that zone and the

interior. Extremes of temperature are

more pronounced and annual rainfall

rarely exceeds 20 inches. Black and

white spruce are the principal forest

trees, but such typical interior plants as

larch and cattails are absent.

The mosquito fauna of the Sitkan zone

is not greatly different from that of the

coast of British Columbia. The pest

problem in this zone tends to be local in

character. High populations may be

present on coastal flats and in forested

valleys, but the problem does not differ

greatly from that encountered along the

coasts of Washington and British Columbia.

(2) Aleutian.—This zone encompasses

that part of southwestern Alaska beyond

the tree line. It is a continuation of the

Pacific mountain region and includes the

islands of the Aleutian chain. Summer

and winter temperatures are moderate

and annual rainfall is relatively high, but

the almost continuous cold fog and high

winds during the summer prevent the

growth of trees and give to the zone an

aspect similar to that of the arctic coast.

However, grasses rather than typical

tundra vegetation form the prevailing

ground cover ifig. 4). The biota is

reduced and mosquitoes appear to be absent or present in very small numbers

over most of this zone.

(3) Htidsonian.—This zone comprises

most of interior Alaska. It is bounded

on the north by the Brooks Range and

on the south by the Coast Ranges. On

the west it is separated from the Bering

Sea coast by a narrow strip of tundra.

The zone is a continuation of the northem coniferous forest that extends the

full width of Canada and is drained by

the Kuskokwim and the Yukon Rivers.

The best agricultural land in Alaska is

found in the Tanana Valley, which is

part of the Yukon watershed.

The climate is dry with extremes of

temperature—a long cold winter and a

short hot summer. Temperatures in the
8 AGB. HANDBOOK 182, U.S. DEPT. OF AORTOULTUB^

Of EAM

ALASKA

t I Tundro.bor« rocK* ii

I I IntfHor boreol /ortst

^^1 Cooital far«st

FiGXTKE 2.—Biotic provinces of Alaska, adapted from Dice (26), superimposed on

vegetation zones, adapted from a map compiled by Sigafoos (in Hopkins et al.

70, p. 1S6).

PN-no

FiGUEE 3.—Aerial view of Valdez, shovcing characteristic topography of the southcentral Alaskan coast.
THE MOSQUITOES OF ALASKA

PN-811

FiGUBE 4.—West coast of Kiska, showing grasses typical of the Aleutian zone.

(Photograph by Ales Hrdlicka, 1936.)

high 80's are not uncommon in July, and

during midwinter the minimum readings

may remain between —40° and —60° F.

for several days. The average precipitation is about 12 inches.

In undisturbed areas much of the land

is covered with black spruce bogs, commonly referred to as muskeg. The forests are seldom high or dense, and they

enclose large areas of sedge (Carex) and

grass (usually Calamagrostis) meadows,

which are marshy during part of the summer (fig. 5). Drainage is characteristically slow, at least in part because of the

permafrost throughout most of the zone.

Poor drainage and low evaporation during the long winter account for the general prevalence of bogs and swamps.

The mosquito problem reaches its most

serious proportions in this interior zone,

for though mosquitoes may be as numerous on the arctic slope, fewer people are

concerned. In some years troublesome

populations may be hard to find, but during other years a pest population may

cover thousands of square miles.

Following Dice's (26) definition of a

biotic province, areas above the timberline in the Alaska Range, as well as in

the smaller mountain ranges of central

Alaska, are zonal subareas of the Hudsouian zone. So far as mosquitoes are

concerned, it seems best to treat these

tundra inclusions as extensions of the

Eskimoan zone, although there may be

noticeable differences in relative abundance of the species present, as well as a

tendency toward greater diversity of

kinds.

(4 ) Eskimoan.—This zone includes the

area to the north and west of the Hudsonian zone and lies beyond the tree line.

Drainage is to the Arctic Ocean and the

Bering Sea. Extremes of temperature

are not so great as in the interior. The

summers are generally shorter, and cold,

foggy weather is more prevalent. Rainfall is low ; the average for much of this

area is below 10 inches and that at

Point Barrow only a little more than 4.

The nearest approach to trees is

shrubby willows and alders, which in

some favored localities reach a height of

^ to 8 feet. The ground cover consists of a

thick continuous mat of heath, prostrate

willows, sedges, mosses, lichens, and
10 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

Ki-asspR, find it is sonerally referrpd to

as tundra ( ligs. 0 and 7). The surface is

rougli, spongy, and usually waterlogged.

Frozen soil is seldom more than 8 or 10

Inches beneath the surface even in late

summer.

Mosquitoes are perhaps more numerous

tlian in the forestod interior, tliough fewer species are represented. Year-to-year

fluctuation appears to be less, probably

because even poorer drainage and lower

evaporation tend to minimize yearly dif-

..mü

PN-812

FIGURE 5.—Tanana Valley near Nenana, showing marsh pools in the center background.

PN-813

riGURE 6.—Tundra near Teller, shovring lighter areas covered with cottongrass

bloom.
THE MOSQUITOES OF ALASKA 11

FiGUKE 7.—Tundra 5 miles south of Kotzebue. The alder bushes in the foreground

attaia a uiaxiiiiuui height of 3 feet.

ferences in rainfall. The tundra-inhabiting species exhibit greater tolerance

to wind and low temperature than the

mosquitoes of the interior. Frequently

it is necessary to wear a head net over

a parka in order to work or move about

the country in relative comfort.

These four zones reflect prevailing patterns of climate, which determine the as.sociation of species

found there. Since climate is a

measure of average weather conditions taken over a long period of

time, it would be surprising if yearto-year differences in weather did

not have a marked effect on the mosquito population. Such an effect

has, in fact, been demonstrated ^

and is discussed below under Abundance.

Maps 1-12 * show the known distribution in Alaska of the 27 species

that have been collected there. The

records are based on studies that

were obviously concentrated along

the few highways and at localities

easily reached by air or river boat.

These localities are so widely scattered that only the most general inferences may be drawn from the

records. ^^Iien these maps are

compared with figure 2, it is apparent that although most records for

any one species are confined to one

zone, most species have been recorded from two, and some from all

but the Aleutian zone. In general,

the distribution shows a close relationship to the tree line. Actually

this relationship is closer than indicated by the maps, which are drawn

at too small a scale to show many

islands of tundra that are included

in figure 2 and map 9 as forested,

or to show the sinuous bands of

forest that follow stream courses for

many miles into the typical tundra.

Abundance

Records of mosquito conditions

at Fairbanks for 1929-31 and 1947-

53 show that pest populations of se-

' Unpublished data of Alaska Insect

Control Project.

* See Api>endix, p. S7.

rious proportions were present during 1929, 1948, and 1919. During

the remaining 7 years the mosquito

problem was not materially different from that to be expected in uncultivated areas of the Eastern
12 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

United States. The Fairbanks

data, supplemented hy similar data

coverinfi 1951 and 1953 for the central Alaskan localities of Foi-t

Yukon, Nenana, and Tan ana, all

show that each summer of unusual

mosquito abundance has been preceded by a period of aljove-noiTnal

precipitation.

That this is true is not surprising, for the species of greatest pest

importance are known to develop in

temporary pools formed from melting snow and ice, and water must

remain in these pools for tlie period

required for mosquito development.

Under the climatic conditions of

central Alaska, snow ordinarily accumulates from October tlirough

April. At brealnip, wliich usually

occurs during early May, the snow

melts and forms innumerable pools,

the duration of which is determined

by (1) the amount of accumulated

snow, (2) the moisture content of

the soil at the time of the freezeup,

and (3) the rate of evaporation and

replacement during May and June.

The last factor appears to be the

least important, for May and June

are months of consistently low rainfall and high evaporation. By

contrast, the first two factors are

extremely variable and may combine to give an exaggerated effect

or tend to cancel each other. Thus,

above-normal snowfall may thaw at

breakup and be lost in abnoniially

dry soil, with the consequence that

few mosquitoes are produced.

Present evidence indicates that

the abundance of mosquitoes is more

uniform from year to year at tundra

localities than in central Alaska.

Umiat is known to have had a severe mosquito problem each summer from 1947 until 1952. Yet

there is ample evidence that pest

populations are not present every

year at all tundra localities, for the

population at Umiat was not troublesome in 1953 and few mosquitoes

were present in 1951 at Teller,

where they were abundant in 1953.

In addition, local residents of

Kotzebue, Teller, and Nome have

reported that, although troublesome mosquito populations are present in most years, there are summers

when few mosquitoes are seen.

Presuinably the more constant

year-to-year abundance of mosquitoes in the tundra areas of western

and northern Alaska is the result

of reduced evaporation during the

short cool summers. One effect of

reduced water loss would be the averaging out of unusual departures

from nonnal precipitation, and

thereby greater uniformity of conditions favorable to mosquito development would be assured in both

a regional and a year-to-year sense.

PREDICTING ABUNDANCE

Ability to predict mosquito abundance in advance of adult emergence

has definite and rather obvious advantages. Even a month's advance

information would permit improved

coordination of control programs

and distribution of supplies to areas

of greatest need. It would also be

advantageous if mosquito conditions could be anticipated before a

work crew or .survey party is sent

into a remote area. Sometimes it

might be desirable to plan the work

so it would not coincide with the

season of adult activity, or the work

might be done at an alternative locality where no mosquito problem is

expected that season.

Present data ^ indicate that reasonably accurate predictions of

mosquito abundance can be made

for those localities in central and

arctic Alaska where weather records have been maintained long

enough to provide reliable average

° SAILER, R. I., RéGNIER, A. V., and McGUIRE, J. U. USE OF PRECIPITATION DATA

FOR PREDICTING MOSQUITO ABUNDANCE IN

ALASKA. Unpublished report of work

conducted with the cooperation of the

office of the Surgeon General, U.S. Department of the Army, and assistance

of the Arctic Institute of North America.
THE MOSQUITOES OF ALASKA 13

annual precipitation values. Two

years' oíjservations at three localities in central and two localities in

arctic Alaska have shown that abundance of mosquitoes is correlated

with departure from normal precipitation, and that the best correlation

is found when departure is based

on a 36-month period preceding

May 1 of the season for which predictions are to be made.

Presumably the 36-month precipitation interval is necessary in order

to account for soil-moisture conditions preceding the last winter's

snow accumulation. The greater

effect of precipitation received during the immediately preceding winter and summer on mosquito abundance makes it necessary to divide

the 36 months into summer periods,

which include the months of May

througli September, and winter periods, which include the months of

October througli the following

April. Weighted values must then

be assigned to departure from normal precipitation for each of the

three summers and tliree winters.

The scheme of weights that provided the best correlation with observed abundance was 3-l-3-l--1^4.

Figure 8 shows the results of the

observations made at the five Alaskan localities during the summers

of 1951 and 1953. The counts

shown were based on the number

of mosquitoes captured in eight 180-

degree sweeps with a 15-inch

Ward's professional insect net, four

sweeps taken on the lee and four

on the windward side of the obMOSQUITO COUNTS AS RELATED TO PRECIPITATION

Economic Importance:

SLIGHT LOCALIZED REGIONAL

cour

60

40

20

1

«

1 y

• 1^/

• mmmm^ 1

I -I-

-40 -20 0

% OF NORMAL PRECIPITATION

20 40

PN-815

FIGURE 8.—Regression of mosquito counts on departure from normal precipitation

for 36 montli.s computed as six consecutive summer and winter intervals, a-ssigned

weights of 3-1-3-1-4-4. Vertical sections labeled .slight, localized, and regional

indicate the economic importance of mosquito populations expected to be prevalent

under corresponding ranges of departure from normal precipitation. Based on

data obtained in 1951 and 1953 at Xanana, Nenana, Fort Yulion, Kotzebue, and

Teller.
14 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

server. Tlie first sweep was made

at the Iniee and the fourth at shoulder level. Counts were made hourly at a sheltered site and at a site

exposed to the wind. Each count

was preceded by a 5-minute period,

during which meteorological observations were made. This provided

a standard exposure period, during

which mosquitoes were attracted to

the observer. At no time was a repellent used.

So far as possible the observation

pei'iod at each locality included 24

hours of optimum conditions for

mosquito activity. To minimize the

eti'ect of transient weather conditions on mosquito activity, the 10

highest counts obtained at each

locality were averaged. On the

chart the average count for each locality for each year was plotted

against the weighted departure

from normal precipitation for that

locality and year.

Using the 3-1-3-1-4-4 scheme of

weights, the precipitation departure equals

3f+le+3d+lc+41)+4a

16

where a equals actual departure

from normal precipitation for the

immediately preceding winter and

b for the preceding summer. The

remaining letters represent the

other preceding winter and summer

data in seasonal sequence to the beginning of the 36-month precipitation period.

The regression line shown in figure 8 was fitted to the data by the

least squares method. The shaded

area on either side of the line represents the calculated 95-percent

confidence limits indicated by the

available data. The regression line

becomes straight when placed on a

semilogarithmic scale.

The actual value of this effort to

correlate mosquito abundance with

precipitation will depend on how

accurately the correlation can be

used to predict populations of

slight, localized, and serious regional economic importance (fig.

8). The regression indicates that

at a locality where the 36-month

weighted departure is more than

30 percent deficient, men should be

able to live and work in the field

with little prospect of mosquito annoyance. If the departure is between 30 percent deficient and 10

percent excess, complete protection

from mosquitoes will be required

in some localized areas. These

areas will become more numerous

and larger as the departure approaches the upper limit. Above

10 percent excess the mosquito-infested areas fuse, and an evenly distributed pest population may cover

hundreds of square miles.

Limited experience obtained from

predictions made for several localities in the suminer of 1956 suggests

that an early breakup followed by

a prolonged period of above-normal

temperatures may cancel the effect

of excess accumulated precipitation,

with the result that few mosquitoes

are produced at a locality where a

severe outbreak would otherwise be

expected. However, it seems

doubtful that a late breakup and

cold spring would result in a serious

mosquito problem where a population of little consequence had been

expected. Data supporting this

contention are lacking, but there is

no evidence of a general hatch of

Aedes eggs in pools formed as a

result of spring rains. Furthermore, abnormal rainfall would be

required to maintain such pools

long enough for larval development to be completed. If further

experience confirms these views,

errors in prediction will generally

be in the direction of fewer mosquitoes than expected.

EFFECTS OF WEATHER ON

MOSQUITO ACTIVITY

"Weather is the paramount factor

affecting adult activity, even though

the northeiTi mosquitoes are remarkably well adapted to their rig-
THE MOSQUITOES OF ALASKA 15

orous environment. Of the various

elements of weather, temperature is

the most important, for during a

period of 24 hours the mosquitoes

are commonly subjected to temperatures both above and below those

at which flight activity normally

occurs.

With the possible exception of

Oulex territans, all species are

crepuscular; however, this habit is

modified by light conditions ¡peculiar to high latitudes. Periods of

gi'eatest activity tend to coincide

with twilight, the highest peak occurring in the evening and a lower

peak in the morning. In latitudes

north of the Panhandle wliere there

is no complete darkness during the

mosquito season, the drop in activity between the peaks coincides with

the rapid fall in temperature that

occurs during the short period when

the sun is below the horizon. Over

much of the area north of the Arctic

Circle the effect of temperature is

even more pronounced, although

the sun does not set.

During favorable weather, mosquito activity on the tundra is more

nearly continuous than in central

Alaska, building up from a low of

near zero between midnight and 2

a.m. to a peak between 8 and 11 p.m.

Periods of calm, cloudy weather

during the day are usually accompanied by increased activity.

However, any prolonged cloudiness

results in lowering the temperature, which soon falls below the

threshold of activity.

At Kotzebue and Teller, periods

of intense activity and relative freedom from mosquito annoyance follow a pattern that must be characteristic of the western seacoast.

This pattern is controlled by a

cyclic kind of weather, whereby 2

or 3 warm, fair days are followed

by a week or more of cold, wet,

windy days.

Although the factors affecting the

activity of the adult female mosquito are well established, they

551810 0—61 2

never function independently, and

their effects in combination are

often very subtle. The factors having the greatest effect are temperature, light, wind, saturation deficiency, lapse rate, and pressure

change.

Temperature.—Pratt [90) found

in his study near Fairbanks that

most activity occurred between 45°

and 80° F., with 60° approximately

optimum. Jachowski and Schultz

{75) reported similar findings for

the arctic species at Umiat. Unpublished data ^ from Kotzebue and

Teller show considerable activity

at 42° and some at 40°. It is likely

tliat factors other than temperature

suppress activity above 80°, for at

such times the sun is usually bright,

the saturation deficiency is high,

and a moderate wind may be

blowing.

Light.—Direct correlations of

activity with light are difficult,

because other factors such as temperature and saturation deficiency

are closely related to light. Nevertheless, most workers have been impressed by a daily rhythm of activity, which may be suppressed or

even displaced by combinations of

adverse or favorable factors other

than light. If other factoi-s are

constant, counts on which activity is based average highest at a

light intensity approaching twilight conditions.

Wind.—In central Alaska, mosquito activity subsides abruptly at

wind speeds above 2 miles an hour

and drops to zero at about 5 miles

per hour. At tundra localities the

arctic species are not noticeably affected by wind at speeds below 5

miles per hour, but begin to disappear when the velocity reaches 7

miles per hour. If other conditions

are favorable, a few will persist

even at a velocity of 10 miles per

" Report by R. I. Sailer, A. V. Régnier,

and J. U. McGuire.
16 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURK

hour. Wind velocities appear to

have an exaggerated effect when

temperatures are near the upper

and lower threshold values. At low

temperatures this effect has been

observed at Kotzebue and Teller,

where considerable activity was observed at 43° to 45° F., but only if

the wind velocity was below 1 mile

per hour. Hocking et al. (GS)

point out that at high temperatures

greater wind A'elocity increases

evaporation and may affect mosquitoes in the same way as high

saturation deficiencies.

Saturation deficiency.—Numerous attempts, including that of

Pratt (90), have failed to show a

clear correlation between relative

humidity and mosquito activity.

Yet all who have observed mosquitoes in the field agree that moisture

must play an important role. This

discrepancy is easily explained, for

relative humidity is not a reliable

measure of the capacity of air to

hold moisture. When Hocking et

al. (68) converted their humidity

data to saturation-deficiency values,

they were able to demonstrate a correlation with activity. However,

the effect appeared to be delayed,

with attack figures rising shorlly

after a fall in saturation deficiency

and falling shortly after a rise.

Lapse rate.—Lapse rate is a measure of rate of temperature change

from the ground level up. Pratt

{90) found that mosquito activity

was greatest during inversion conditions when the surface temperature was below 45° F. at the 3-foot

level. With more extreme inversion

conditions when the temperature at

5 feet was below 45° and warmer

temperatures were above head level,

no mosquitoes were found at body

level, but they were seen flying in

the warmer air overhead.

Pressure change.—Haufe {61) in

laboratory experiments with Aedes

aegypti (L.) found changes in atmospheric pressure to be an important factor in determining flight

activity, provided the mosquitoes

were first acclimated for 3 to 6

hours to a particular level. When

the pressure was above 735 mm., decreasing the pressure was more

stimulating to flight than increasing the pressure; whereas when it

was below 735 mm., the opposite

was obtained. Although field data

concerning the northern species of

Aedes are still lacking, failure to

consider pressure change as a factor may explain some discrepancies

in past attempts to correlate mosquito activity with meteorological

data.

Biology

LARVAL HABITATS

When compared with the more

temperate parts of the world,

Alaska has noticeably fewer kinds

of habitats in which mosquito larvae can live. Tree holes are an example of a missing habitat. No

doubt such water-containing cavities exist in southeastern Alaska,

but over the rest of the State they

are absent either because the trees

are small or because of frost action.

With the exception of Culiseta, no

species are known to breed in artificial containers.

The one-generation habit is common to all species, though at Anchorage a small second hatch of

several species of Aedes has been

observed during August after

heavy summer rains. The species

of greatest pest significance hatch

within a few days after the spring

breakup, or as soon as the snow or

ice has thawed from the bottom of

the pools. Most of the pools are

temporary and originate from melting snow.

A practical system of classifying

larval habitats is one based on the
THE MOSQUITOES OF ALASKA 17

degree of pool permanency, for to a

great extent this factor detei-mines

other pool characteristics such as

vegetation type, as well as presence

and abundance of predators. Pool

types may be characterized as temporary, semipermanent, and permanent.

Temporary.—These pools of

snowmelt origin normally are dry -i

to 5 weeks after the spring breakup

(figs. 9 and 10). They are found

in widely different locations and

support a \'ariety of emergent and

covering vegetation. The most important pools to the mosquito problem are those in Carex or Calamagrostis marshes and in f^phagnitmheath bogs. The marshes are shallow and vary in size from a few

square yards to many acres. In central Alaska they are interspersed

throughout the spruce and birch

forests of lowland or level country.

Tlie flats along the southern coast

include large areas that are covered with Myñca-Carex marshes.

Sphagnmn-hft.nûi bogs commonly

support stands of scrubby black

spruce and form the muskeg so characteristic of the subarctic region.

Except for deep potholes or ponds,

both marshes and muskeg are

largely dry during the last part of

the summer.

Few predators are found in

temporary pools.

Semipermanent.—These pools or

ponds that are formed from snowmelt are maintained to some extent

by seepage or a high water table.

In normal yeare the pools are dry

for at least a short period during

July or August. Carex rostrata^

Potentilla pahtsfria, and Equisetum

fhtviatUe are among the plants most

often associated with pools of this

kind (fig. 11). On the tidal flats

(fig. 12) Triglochin maritiina and

Scirpus paludosun are indicative of

the semipermanent condition (fig.

13 ). Such habitats are numerous in

river valleys where there are many

oxbow lakes.

PN-816

FIGURE 9—Temporarv pools in Myrica-Calarnngrostis marsh near Fairbanks, where

Aedes intriidcns, commiinis; and punctor were collected.
18 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

FIGURE 10.—Temporary pools hidden in Calamagrostis marsh near Anchorage.

PN-818

FiGUKE 11.—Semipermanent pool near Anchorage, where Aedes excrucians and

fitchii larvae were numerous.
THE MOSQUITOES OF ALASKA 19

Predators are prevalent in semipermanent pools. Chaoborids, dytiscids, and Gallicorixa (Corixidae)

are often present in numbers sufficient to greatly reduce the population of mosquito larvae.

Permanent.~T\\^^Q ponds and

lakes normally contain water

through the summer (fig-s. 14, 15).

Lemna., Ranunculus, and Vtrlcularia are common, and Carex aquatilis often forms an emergent cover.

FiGUEE 12.—Eagle River Flats, a tidal marsh near Anchorage.

FIGURE 13.—Semipennanent pools on Eagle River Flats near Anchorage, vs'here Acdefi

flavescens larvae were found. These pools were seldom more than 2 inches deep

and nearly continuous over the marsh.
20 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

FiGUBE 14.—Permanent pond near P^alrbanks. Culi^eta alaskaensis and Aedes

excrucians are the predominant species.

PN-822

FIGURE 1.5.—Permanent pond near Anchorage. Habitat of Anopheles earlei and

CuJex territans.
THE MOSQUITOES OF ALASKA 21

Predators are abundant. Odonata naiads and dytiscid larvae and

adults are always present in large

numbers.

Habitat Preferences and Relative Economic Importance of

Species

From data obtained in 1948 by

the Alaska Insect Project, the species have been tabulated according

to the kinds of pools utilized as larval habitats. The percentages

shown in table 1 are estimates based

on the number of times species were

collected from one or more of the

pool types and on their relative

abundance.

Such an arrangement, based as it

is on relative permanency of the

pools, is unsatisfactory in several

respects. It would be possible, and

sometimes desirable, to establish additional divisions based on such

factors as shade, presence or absence

of vegetation, and kind of emergent

or covering vegetation. There is

also a marked tendency for species

TABLE 1.—Species of mosquitoes arranged according to kinds of habitats

from tohich larvae have been collected in central and arctic Alaska and

their relative economic importance

Species

Percentage of species collected in

différent kinds of pools

Temporary

Semipermanent

Permanent

Relative economic importance '

Central

Alaska

Arctic

Alaska

Aedes intrudenscanadensis ^-

implicalus _ .

communis- _

punclor

hexodontus-.

impiger

diantaeus

cataphylla ^

pionips

nigripes ^

pullatus ^

cinereus

Stimulans

flavescens

riparius ^

excrucians

fitchii

aboriginis ^

declicus

Culiseta alaskaensis.

impatiens

incidens ^

morsitans

particeps ^

Culex terrilans

Anopheles earlei

100

+

80

70

70

60

60

50

+

+ ' +

40

30

+

20

.30

30

40

40

50

+

60

+

-t70

100

100

+

+

70

70

60

80

80

70

30

30

+

40

20

20

30

60

40

40

60

' 1 Widely distributed, a pest species during years of unusually high abundance; 2

widel'y distributed, locally troublesome, especially durmg y.*^^^^ °f "¡^„ffJ^SeTv

3, restricted distribution, but abundant under certain f°l«g'f' °°"^'t°A'A bltlman

distributed, but not in large numbers; 5, widely distributed, but not known to bite man,

^' ' D'atT'absInt or too scanty to generalize. Plus marks indicate that the species has

been collected in a particular pool type.
22 AGR. HANDBOOK 18 2, U.S. DEPT. OF AGRICULTURE

that commonly develop in tempoi-ary pools in central Alaska to utilize semipermanent pools in areas

beyond the tree line. Tlie explanation of tliis plienomenon may lie

concerned with the relative scarcity

of predators in the tundra pools.

A well-marked succession of species based on tlie time of peak emergence generally follows tlie order in

which they are listed in tal>le 1,

beginning with those that develop

entirely or mainly in temporary

pools and ending with those that

utilize semipermanent or permanent

pools as larval habitats. Tlie time

during which emergence of a species may occur l^ecomes shorter toward tlie north or in any diiection

toward the tree line, and species

succession is more clear cut. Tlie

Culiseta species, as well as Anopheles earlei and Culex terrttam.

which are at or near the end of the

succession, all overwinter as adults.

Water Temperature of Larval

Habitats

Hatching of mosquito eggs, at

least of those species developing in

temporary pools, occurs as soon as

the ice over the bottom of the pools

melts. In shallow pools and in the

pi-esence of bi-ight sunlight this may

liappen befoi-e the air temperature

has readied or passed 32° F. Subsequent to thawing, the pools often

freeze solid without injury to the

newly liatched wigglers.

It is a common conception that if

ice is present in a small pool, the

water temperature cannot exceed

.39.2° F. If this were true, some

species of mosquitoes Avould complete most of their development at

temperatures of less than 40°.

Through detailed studies of vertical

and horizontal temperature gradients, Pratt (90) was able to show

that development actually occurs at

a much higher temperature. As

illustrated in figure 16, marked

temperature gradients exist within

a pool during periods of sunlight,

and water in one part of this pool

may be well above 50° even though

ice i s present. Larvae were always

found congregated in the warmest

water. No larvae were found in

deep pothole pools in which the

Avater never exceeded 40°.

PN-823

FiGUEE 16.—Diagram of a pool in which mosquito larvae are developing, showing

temperature gradients during a warm, sunny day when ice is still in the pool.
THE MOSQUITOES OF ALASKA 23

ADULT FOOD HABITS

Most discussions of mosquito

feeding habits are concerned with

the bloodsucking activities of the

females. Actually, plant juices

and nectars must foma a pi-eponderance of the food consumed by

mosquitoes. Males are restricted to

such foods, and females apparently

seek blood meals only as a source of

nitrogen needed for egg production.

Hocking et al. (68) presented

evidence that feeding on nectar is

a universal habit among females of

the arctic and subarctic species at

Churchill, Manitoba. The tremendous number of mosquitoes in many

arctic or subarctic areas in contrast

to the negligible population of vertebrates has roused speculation that

these species may not require a

blood meal in order to produce eggs.

Beckel (12) obtained laboratory

evidence that Aedes communis females were able to produce viable

eggs when fed only on sucrose

or raisins. Furthermore, Beckel

could not induce communis females

from the Churchill area to take a

blood meal in the laboratory, nor

were positively identified females

observed to take blood meals in the

field. Neither did he find evidence

of flight-muscle autolysis such as

Hocking {67) found in specimens

of morphologically similar communis. In any event, there is clear

evidence that at least some of the

arctic Aedes species do not require

blood for egg production. Undoubtedly the smaller vertebrates

such as birds and their nestlings, as

well as field mice and lemmings,

form a larger source of blood than

might be suspected. In a population like that studied by Hocking,

resort to muscle autolysis as a source

of nitrogen may be a secondary response that occurs only after the

females have failed to obtain a

blood meal within a prescribed

time.

Females of Culex terñtans and

CuUseta inorsitans are not known

to bite man or other warm-blooded

animals. ('. terrítans is known to

feed on frogs.

Consideralile research has been

done recently on factors that attract

female mosquitoes to a host. Hocking {06) has provided a summary

and bibliography covering this

work. Evidence indicates that

temperature, moisture, and carbon

dioxide are the principal attractants for the northern mosquitoes.

As would be expected, these factors

are most effective when functioning

in combination. Light colors have

l)een found to be less attractive

than dark colors to some species,

but this order of preference is reversed for others.

LONGEVITY

The adult life span of the northern Aedes species is probably not

more than 8 weeks in central Alaska

and considerably shorter beyond the

tree line. Very likely the longevity

varies from year to year because of

different weather conditions. The

bloodsucking activity of the females

serves as a partial clue to longevity.

In the Fairbanks area pest populations subside rather abruptly about

a nionth to 6 weeks after peak adult

emergence.

In those species of Anopheles.,

Culex, and CuUseta where the

females overwinter, it is likely that

many individuals have an adult life

of at least a year. However, the

males live only until cold weather.

FLIGHT RANGE

There is little information on the

night range of mosquitoes in Alaska. A large-scale test to control

mosquito larvae near Fairbanks

(Travis et al. 10If) showed that

adult mosquitoes penetrated to the

center of a 100-square-mile area, in

which all larvae had been killed,

within 3 days after they had
24 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

emerged in adjacent untreated

areas. Howevei', when the same

area was sprayed to control adults,

infiltration was sufficient to require

another treatment in about 2 weeks.

If such movement is typical of

untreated areas and continuous

through a 6-week period of activity,

such a population might disperse

a distance of 2.5 to 50 miles.

Several factors undoubtedly

affect the movement of mosquitoes.

One of the most important is the

habits of the different species.

Such a species as Aedes einereus is

seldom found except in vegetation

near its breeding place. In the

only large-scale study undertaken

on the dispersal of a subarctic

species, Jenkins and Hassett (77)

released 3 million radioactive adults

of Aedes communis. During tlie

first week no specimens were taken

more than 600 feet from the point

of release, and after a month only

one had been recovered from as far

as 5,000 feet.

The tundra is characterized by a

comparative absence of barriers to

free movement. This factor, combined with the ability of Aedes

hexodontus and nigripes to fly in

wind moving at a velocity twice

that tolerated by woodland species,

provides ample reason to expect the

flight range of these arctic mosquitoes to exceed that of any species

found in central Alaska.

The widely held view of local

residents that mosquitoes are

carried great distances by the wind

has never been confirmed. On the

contrary, mosquito activity has been

repeatedly observed to cease whenever the wind velocity exceeds the

flying speed of the mosquitoes.

Flight activity of the kind that

would promote dispersal has been

observed ^ at times when the wind

velocity was about 1 mile an hour

and when a pronounced temperature inversion caused the air tem-

' See footnote 3, p. 11.

perature near the ground to be

below that at which mosquitoes are

normally active while the air at

treetop level was still warm.

The periods of most intense mosquito activity were found by Pratt

{90) to coincide with times when

moderate inversion conditions were

present. If dispersal activity is

correlated with inversion conditions, it should be possible to predict

the principal direction of such

movements in a given area, for air

movement at such times usually follows a drainage pattern determined

by the topography.

MATING

Except for the dissenting views of

Nielsen and Grève {88), authorities generally agree that mating in

mosquitoes is almost invarialjly

associated with the swarming habit

of the males. Although this habit

appears to be common to all the

Alaskan species, observations by

Frohne and Frohne {39, 4J) and

others show that the time and place

of swarming may depend on the

species.

The Frohnes observed swarms of

Aedes functor containing hundreds

or even thousands of males and

noted that matings in a swarm

occurred at rates of 1 to 10 per

minute and rarely as high as 150

per minute. They also reported

watching swarms of Aedes communis between 8 and 9 p.m. on June

16, 19, 20, and 21. The swarms

occupied the same site about 8 to 10

feet above the ground, in what was

described as a "glade recess." On

June 20 at 9:30 after communis

ceased swarming, they saw a swarm

of Aedes excrucians form at the

same site, but the focus of this

swarm was 10 to 20 feet above the

ground.

All Alaskan species for which

records are available swarm in the

evening except Oulex territans. It

was observed by the Frohnes to
THE MOSQUITOES OF ALASKA 25

swarm between 3:30 and 4:45 p.m. ;

however, they saw no mating.

OVIPOSITION

Of the various biological aspects

of Alaskan mosquitoes, perhaps

least is known of their oviposition

habits. It is known that the Aedes

species lay their eggs in moist depressions, which are subject to flooding at the time of the spring breakup. Eggs of the Anopheles species

are laid on the surface of the water,

and eggs from each deposition tend

to clump together. The Cidex and

CuUseta species deposit rafts of

eggs. Frohne (34) has shown that

Culiseta alaskaensis and impatiens

females are rather discriminating in

their selection of oviposition sites,

alaskaensis selecting small pockets

in emergent clumps of dead Carex

and impatiens ovipositing on open

water devoid of emergent vegetation. Very likely the Aedes species

are also able to detect and lay their

eggs at sites suitable for the larval

development of their particular

species.

Eggs of some northern Aed^s

species remain viable (Gjullin and

Yates 57) forseveral years. Water

having a low oxygen content is

important as a hatching stimulus

for eggs of these species (Gjullin

et al. 51). Additional factors must

also play a part, since not all eggs

hatch even though they are subjected to apparently identical field

conditions.

HIBERNATION

According to Bates {10), there

are four types of season cycles

found among the life histories of

mosquitoes. One of these types includes all the Alaskan species of

Aedes and is referred to as the A.

cinereus type of cycle, in which

there is but one generation a year

and liibeniation is in the ^gg stage.

With one possible exception, the

remaining Alaskan species—those

belonging to Anopheles, Culex, and

CuUseta—belong to a fifth type of

cycle recently described by Frohne

( 3^ ) and referred to as the CuUseta

¡tnpatien-'i type. In this cycle fertilized females overwinter and there

is but one generation a year.

Cidixeta morsitans may overwinter in the larval stage and would

tlius fall in the Anopheles elaviger

type of cycle described by Bates.

The type of season cycle must have

an important bearing on the distribution of mosquitoes in Alaska,

for those species belonging to the

C. impatiens type are rarely found

beyond the tree line, except in

mountainous areas where the tree

line is detemiined by altitude.

Probably these species require the

sheltered habitats associated with

trees as hibernating quarters for the

adult females.

Surveys of the Mosquito Problem

Adequate mosquito surveys and

engineering sui-veys must be made

if control measures are to give satisfactory results quickly and economically. Such surveys are often

initiated by a few interested individuals who wish to leani whether

their local mosquito problem can be

alleviated or eliminated. If control appears to be feasible, then

community action is usually required in order to maie arrangements for operating funds and

proper execution of the control

program.

MOSQUITO SURVEYS

Mosquito sun'eys must be made

by competent entomologists. The

entomologist must determine what

species are present and learn as

much as possible about their biology

and their enviromnent. He should
26 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

establish which species contribute

to the problem and whicli are uncommon or do not bite man and his

domestic animals. Surveys should

extend some distance beyond the

boundaries of the community for

wliich a control program is being

planned, for some species are known

to disperse several miles. Under

Alaskan conditions surveys need not

be concerned with potential disease

vectors but should concentrate on

the few aggressive and abundant

species.

In order to study biting habits

and flight activity, the entomologist

must be able to identify the adult

mosquitoes and also the larvae, so

as to associate them with the type

of water or breeding area in which

they occur. The larvae of some

species live almost exclusively in

pennanent water and others only

in temporaiy water; some prefer

shaded pools and others only pools

well exposed to the sun ; some are

found in polluted water or water

with a large amoimt of decaying organic matter and others only in

clear unpolluted water.

Unfortunately one entire mosquito season is not adequate for a complete entomological survey, as the

species composition and abundance

may vary considerably from year to

year. Several years are often required before the entomological

data are reliable. Fairly effective

control operations can be started

before the surveys are completed,

but without reliable data, control

may be erratic and result in the loss

of public confidence.

Mosquito surveys may provide

additional information of value to

the control director. It is rather

common for critics to maintain that

control procedures are ineffective.

Ifsome reliable figures are available

on the control of species and population densities, these can be used

as proof of results. There is also

a need for standard methods of

observations, so that comparisons

can be made of progress over the

years in each community.

Mosquito surveys normallj^ include the collection and identification of both adults and larvae. In

some areas outside Alaska useful

information has also been obtained

from egg surveys.

Adult surveys.—Several methods

have been used to collect adult mosquitoes, but usually they include

various types of hand and trap

collections.

Hand collections of biting mosquitoes provide the simplest and

most direct method of determining

which are the troublesome species

and the relative abundance of each.

Such collections are usually made

with a killing bottle.

The most useful procedure for

making hand collections in Alaska

is to select representative locations

in the community where daily,

weekly, or biweekly collections can

be made throughout the season.

A normal procedure is to stand or

sit for 1 or 2 minutes at each location and collect mosquitoes as they

alight to bite. Some standard collection time should be used, so that

all data can be comparable. If mosquitoes are not too abundant, one

person can collect in a killing bottle

all those that land on the front of

his trousers. If two people are

working together, one can collect

the mosquitoes alighting on the

back of his companion.

Wlien two or more persons are

to make collections at different

places, they should make some preliminary collections at one place to

determine the relative attractiveness and dexterity of the different

collectors.

Care must be taken in selecting

the collection locations, as some

species bite more freely in the

bright sunlight and some in the

shade, and many species bite more

readily at dusk. The numbers will,

of course, vary with the weather

conditions.
THE MOSQUITOES OF ALASKA 27

A common hand-collecting method in some areas is to catch the mosquitoes in their daytime resting

places, such as dark corners of

buildings, under structures, in hollow trees, or in prepared resting

places such as barrels and boxes.

In Alaska the resting-place collections are not very useful.

Traps furnish data with the least

personal bias, and some types of

traps are more likely to capture

rare species and males than are

taken by hand collections. Traps

are not known to be of any value

for control. They serve only as

a sampling device.

Several types of traps have been

used. One of the most common is

the New Jersey light trap. It has

a light to attract the mosquitoes

and an electric fan to suck them into a cyanide jar, where they are

killed, or into a large cage if live

mosquitoes are desired. Such a

trap may be useful in southern

Alaska, but it is of little value in

the northern areas, since the nights

are not dark. These traps have the

additional disadvantage of capturing many other insects.

In tropical areas it is rather common to use traps baited with some

animal such as a horse or a mule.

Such traps have not been used in

Alaska, but it is thought that they

would be of little value.

A mechanical rotary trap has

been used in Alaska with some success (Chamberlin and Lawson 19

and Stage and Chamberlin 99).

It can be operated by a gasoline

motor and therefore does not depend on electricity or darkness.

Since it catches all insects that fly

within its collecting range, the

exact number of insects per cubic

foot of atmosphere per time unit

can be determined. Another mechanical trap used in Alaska is

made by fastening a screen-wire

cone on the fender of an automobile. With such a trap one can

take continuous samples of mosquito populations while traveling

down a road. Both of these mechanical traps have the disadvantage of damaging the specimens so

tliat identification may be impossible. It may be possible to determine total mosquito counts but not

the species.

In areas where mosquitoes swarm

about people or domestic animals

as they do in Alaska, it is possible

to obtain a good population count

by making a uniform number of

swings with an insect net. For

instance, if a net is swung back

and forth quickly over a uniform

distance and a imiform number of

times, the number caught in each

collection can be used as a population index figure (fig. 17).

A trap that is useful to check

on the total number of mosquitoes

emerging from a given location and

on the species can be made by

placing: a cage covered with screen

Wire or mosquito netting in each oi

several breeding locations to capture the adults as they emerge.

PN-824

FIGURE 17.—Sweep-net method of obtaining a population count, showing

the first of eight 180-degree sweeps

taken from knee to shoulder height.

Four sweeps are made on each side

of the observer.
28 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

Such a trap gave useful information in Alaska.

Larval surveys.—The traditional

way of making a mosquito survey is

to locate the larvae by sampling

various water accumulations with a

white enamel dipper (fig. 18).

Some workers prefer to insert a 2-

or 3-foot-long stick in the handle.

Considerable skill is required in the

use of a dipper. Some larvae, especially the Anopheles^ may be collected best by skimming the water

surface, whereas other larvae may

be more easily captured by submerging the dipper deeply and

quickly. A little experience is

necessary before one can dip successfully. It is common for one

person to collect rather consistently

more than twice as many larvae as

another. With a little effort and

experience, workers can be trained

to obtain rather uniform numbers

with their dips. Ordinarily larval

populations are expressed as the

number of larvae per dip or, if the

larvae are not numerous, the number per 10 dips.

Larval surveys serve to determine

not only the species present but,

even more important, the comparative abundance in the various water

accumulations. They are used to

show which areas should be treated

with larvicides and which areas

have no larvae or too few to justify

the expense.

In larval surveys, records must be

kept of the types of water in which

the larvae are found. In Alaska

Anopheles., Culex., and Guliseta are

typically associated with permanent

water, Avhereas most of the Aedes

are typically associated with temporary water.

The timing of the larval surveys

is extremely important. For instance, nearly all the Alaskan Aedes

eggs hatch as soon as the snow and

PN-82S

FIGURE 18.—Using a dipper to collect mosquito larvae in a semipermanent pool near

Ancliorage. Aedes communis and punctor larvae developed in marginal areas.

Large numbers of Culiseia impatiens and alaskaensis emerged later from pools

where water remained longest.
THE MOSQUITOES OF ALASKA 29

ice start to thaw in the spring, and

in central Alaska neariy all larvae

have matured by the first week in

June. Surveys made after the first

of June may show very few larvae

present, and these are more apt to

be the less numerous Anopheles,

Culex, or Culiseta.

Egg surveys.—Although no ^gg

surveys have been made in Alaska,

several methods have been used to

study the distribution of mosquito

eggs in other areas.

The different egg-laying habits

necessitate different types of survey

methods. AnopJieJes, Cidex, and

Culiseta ^gg surveys have been

made by skimming the water with

fine strainers such as bolting cloth

or by straining water through

folded cheesecloth. The Culex and

Culiseta egg rafts can be seen floating on the water. Aedes egg surveys have been made by sampling

the soil where the eggs are laid.

Three types of mechanical devices have been used to sample

Aedes mosquito eggs. One method

uses a modified vacuum cleaner

(Husbands 7^) to pick up the eggs.

The soil and debris are then removed with screens and the remaining soil is examined for eggs under

a microscope. The other two methods employ a modified grain cleaner

(GjuUin Jf9) or a series of three

concentric screen cylinders in a water bath (Horsfall 71) to remove

the bulk of the soil from hand-collected samples.

A simple metliod to sample Aedes

mosquito eggs is to take soil samples

to the laboratory and flood them

with water. As many eggs may

have a resting state known as diapause, they may not hatch well except in the spring.

ENGINEERING SURVEYS

Engineering surveys are most effectively made after the entomological information has been assembled,

or they may often be made concurrently. The purpose of these surveys is to ascertain from the critical

topographical features of the mosquito-producing areas whether control can include such permanent

measures as water removal through

drainage or fills or whetlier temporary control with insecticides is the

only indicated method. The engineering survey must determine the

extent and nature of the water

accumulations and whether the

water is permanent or temporary.

It can be made by a sanitary engineer or a mosquito-abatement engineer in cooperation with an entomologist, or by an entomologist who

is familiar witli the engineering

aspects of mosquito control.

Methods of Mosquito Control

Mosquito control in the arctic and

subarctic regions received almost no

attention prior to 1940. Although

the tremendous populations of mosc[uitoes were known to those who

lived or worked in Alaska, it was

not until 1947 that comprehensive

studies were started by civilian and

military organizations to api^raise

the problems and to investigate the

practicability of controlling these

pests.

As mosquitoes can fly several

miles from their breeding places

{16, 100), there is often little that

an individual can do to obtain adequate control. The most satisfactory program is provided when

entire communities coordinate their

efforts.

Since the midforties, when the

organic insecticides first came into

general use, mosquito control has

become more and more complicated

but at the same time more effective.

Now, if control with insecticides is

indicated, one must decide which of

several insecticides, which formula-
30 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

tions, and which of the many complicated pieces of equipment to use

{107).

A complete program for mosquito

control today is directed not only

against the larvae but also against

the adults in and around buildings

and in large areas. No satisfactory

methods have been developed to control mosquitoes in the egg or pupal

stage.

CONTROL OF LARVAE

Mosquitoes can usually be controlled most easily and cheaply

while they are in the larval stage.

Two methods have proved useful—

environmental control, which is

more permanent, and control with

insecticides, which is temporary

U)-

Environmental Control

Wherever possible, the water in

which mosquito larvae are found

should be eliminated by drainage,

fills, and manipulation of water

levels {63). Drainage and fills are

undoubtedly the most certain methods of eliminating mosquitoes, but

the costs of such operations are

high. Although these methods

have been used successfully in many

temperate and tropical areas, prospects for general use in Alaska are

not promising. The usually large

and inaccessible breeding areas, the

permafrost, and the high water

tables characteristic of much of tlie

region impose severe limitations on

control by drainage. The use of

fills is even less practical. Where

fills are made, care should be taken

that they do not interfere with natural drainage, and all borrow pits

should be opened to the natural

drains. Drainage and fills are

likely to be of use only in or near

well-populated communities.

Drainage is accomplished by digging a series of ditches to remove

the water from locations where

mosquito larvae are found. For

this method to be effective, the

water level of the breeding area

must be higher than the natural

drainage systems, such as streams,

lakes^ and the sea. If the breeding

a rea is higli enough, the ditches will

either keep the land free of water

or else carry any larvae into the

natural drainage systems. In

many communities road fills have

blocked natural drainage, and in

such locations large numbers of

mosquitoes may be produced. The

proper use of drainage culverts

will correct the roadside water

accumulations.

To be effective, ditching systems

must be kept under annual surveillance and must be maintained.

Some ditches will need cleaning

every year or so, lest they become

clogged and cause flooding that may

produce more mosquitoes than in

the unaltered breeding areas.

Mosquito control by manipulating water levels has proved satisfactory in many areas and may be

of value in special locations in

Alaska. A typical procedure is to

construct dams across the outlets of

lakes and ponds to hold the water

level constantly high and thereby

limit the area of marshland on

which eggs may be deposited.

Ditches may be dug along the impoundment margins parallel to the

elevation contours to receive seepage and other water accumulations,

which should then be drained into

the main impoundment by way of

secondary ditches. This method is

most effective if the margins of the

impounded area are steep, so that

there is a minimum of shallow

water, and also if they are free of

vegetation.

An important aid to the control

of mosquito larvae in impounded

waters, such as the TVA water

systems, has been the removal of

submerged vegetation along the

shore as well as within the main

water area. Mosquito larvae do

not survive long in open water that
THE MOSQUITOES OF ALASKA 31

is deep, free of vegetation, and

subject to considerable wave action.

Control With Insecticides

Wliere it is not feasible to eliminate mosquito-breeding places, the

larvae may be controlled with insecticides. Although this method

is only temporary, it has a more

lasting effect in Alaska than in

many areas. In warmer climates

there may be several broods each

season, each of which would require

treatment. In Alaska the principal

problem is created by the Aedes

mosquitoes. Since there is only one

brood each year, a single well-timed

application will eliminate most of

the larvae for an entire season {29,

^2,75, 76).

Two methods of applying insecticides have proved satisfactory

in Alaska. They may be applied

either to the water for direct control of the larvae or to the soil or

snow as a prehatching or preflood

treatment before the eggs hatch.

Hand sprayers of the Flit-gun

type are satisfactory for spraying

small puddles. Areas of an acre or

more can be treated with a 3- to 4-

gallon compressed-air or knapsack

sprayer. Larger areas can be

sprayed by aircraft (.?, 73).

Application to water.—Fuel oil

No. 2 and diesel oil have been

widely used to control mosquito

larvae and are still used under some

conditions. From 15 to 50 gallons

per acre usually gives good results

when sprayed on the water. As

little as 6 gallons per acre has been

effective when 3 to 5 percent of a

spreading agent has been added.

Three satisfactory spreading agents

are sulfonated sperm oil (Nopco

1216), a phthalic glyceryl alkyl

resin (Triton B-1956), and an 18-

carbon-chain complex amine

(Amine230X) {82).

The pyrethrum larvicides developed in New Jersey have been successfully used in many regions, par551810 O—61 .3

ticularly in garden pools containing

valuable aquatic plants or fish {Iß).

However, tlie cost is too high to recommend them for use in the extensive mosquito-producing areas of

Alaska. Rotenone and creosote

have received some publicity from

time to time, but it was not until

DDT became available that control

with insecticides became really feasible. Since then several other insecticides have been developed.

Tlie most practical ones from the

standpoint of effectiveness and cost

are TDE, BHC, lindane, toxaphene, heptachlor, dieldrin, malathion, and parathion. With these,

satisfactory control can be obtained

with strikingly small dosages, from

0.075 to 0.4 pound per acre, depending on the insecticide {50, 56).

An oil solution is one of the most

practical formulations of DDT

{103, J04). Concentrations of 1 to

5 percent of DDT in fuel oil No. 2,

diesel oil, or kerosene are the most

widely used for ground equipment,

and 20 to 25 percent prepared with

auxiliary solvents for air spraying.

A good auxiliary solvent for a 20-

percent DDT solution is a methylated naphthalene such as Velsicol

NR-70, Solvesso No. 3, or Shell 42.

The addition of 0.25 to 0.5 percent

of Triton B-1956 increases their effectiveness. Emulsions are also satisfactory, but they are not recommended where fish and wildlife

would be affected. Several emulsifiable formulations are available.

A typical one contains 25 percent of

DDT, 65 percent of xylene or other

solvent, and 10 percent of Triton

X-100 or other emulsifier. The

dosage for the immediate control of

larvae in Alaska is 0.05 to 0.1 pomid

of DDT per acre {103, m).

TDE, which has a low toxicity to

fish, is useful in waters where fish

are present. It may be used in the

same fomiulations and applied at

the same rates as DDT.

BHC and lindane usually give results about equal to DDT, but oil
32 AGR. HANDBOOK 182, U.S. DEPT. OP AGRICULTURE

solutions are difficult to prepare and

these insecticides are not particularly useful in Alaska. The dosage

should not be more than 0.05 to 0.1

pound of the gamma isomer per

acre, owing to the toxicity of these

insecticides to fish.

Toxaphene can be used either in

oil solution, as described for DDT,

or in emulsion. The dosage should

be 0.2 to 0.4 pound per acre. In

Alaska toxaphene has not given results equal to DDT, and it is much

more toxic to fish. Heptaclilor has

not been tested in Alaska but was

effective in Utah when applied in

emulsion at 0.05 pound per acre

{60). Dieldrin has been used at

about 0.1 pound per acre in oil solution and emulsion. Toxaphene,

dieldrin, and heptachlor are two to

four times as toxic as DDT to mammals and should be handled accordingly.

Use of most of the organic

phosphorus compounds must be

supervised carefully, as several of

them are toxic to man and animals.

They should not be used for routine

control unless resistance to DDT

and the other common insecticides

has been confirmed. Malathion,

one of the least toxic of these materials, is being used in California

{m, 56,102) at 0.4 to 0.5 pound per

acre. Parathion is likewise being

used in California and Utah {102),

but special care must be taken in

handling this material and it must

not be applied over inliabited areas.

The dosage is 0.075 to 0.1 pound per

acre, or 0.02 p.p.m. in water. Dipterex» (dimethyl 2, 2, 2-trichloro1-hydroxyethylphosphonate) and

parathion have been added directly

to water in irrigation ditches in

California (4<5) and Arkansas {¡¡.ß)

by means of an automatic applicator (^) before the water flowed

over pastures and fields. Control

'The mention of proprietary products

does not imply their endorsement by the

U.S. Department of Agriculture over similar products not named.

for distances of about one-half mile

has been obtained by this method.

An important recent development

in insect control has been the use of

granulated insecticides {60, 108,

110^ 111, 112). The granules are

easily distributed by airplane,

ground equipment, or hand. They

liave enough weight so that they are

not so subject to wind drift as

sprays or dusts and will penetrate

vegetative canopies and thus reach

mosquito breedmg areas.

Prehatching treatments.—Prehatching treatments have been successful in Alaska {106). The insecticides are applied to the dry or

moist ground in the late summer or

fall or on snow (fig. 19) before the

spring thaw {8S, 96, 116), and

hatching larvae are killed by the

residues. The best results have

been obtained in areas that are dry

in the late summer and early fall

and wet only in the early spring.

Prehatching treatments may be

made with any of the DDT formulations. One to two pounds per

acre will give control for two or

more seasons in all but seepage

areas, where 2 pounds may be ineffective for even one season.

These heavy applications should be

made only in areas where there is

no danger to wildlife. Much

lighter dosages of DDT applied as

adulticides have been found to serve

as effective prehatching treatments

for at least two seasons. In a 100-

square-mile plot that had received

a total of 0.3 pound of DDT in

three treatments in 1949, less than

5 percent of the expected number of

larvae were found in 1951 {6).

PROTECTION AGAINST

ADULTS

The control of adult mosquitoes

is often more expensive than the

control of larvae, as the adults disperse over wider areas. Because of

recent developments individuals

and communities may now be pro-
THE MOSQUITOES OF ALASKA

PN-e26

FiGUEE m—Applying DDT dust as a prehatchlng treatment on snow at Anchorage.

vided with fairly satisfactory protection against adults. The two

primary methods used are the personal protective measures and insecticide applications.

Personal Protection

Where mosquito control is not

feasible or when a brood inadvertently emerges in a control area, it

may be cheaper and more practical

to use such personal protective

measures as screens, bed nets, head

nets, and repellents.

Screening of all windows and

doors with screen wire of 16 meshes

to the inch or smaller is a common

practice, and in fact a necessity in

most communities (8). Bed nets

are necessary for campers and

people not living in screened houses,

as well as for those who work, hunt,

or fish outside control areas.

Under extreme situations gloves

and two thicknesses of clothing

provide adequate protection.

When properly applied to the

neck, face, and hands, repellents

prevent mosquito bites for several

hours, the actual length of time being dependent on the person, the

type of repellent used, the species

of mosquito, and its abundance (2,

¿, 7). Liquid repellents may also

be sprayed lightly on garments to

prevent mosquitoes from biting

through clothing.

The most effective mosquito repellent now available is diethyltoluamide (4-7, 97). It also provides

protection from other common

Alaskan pests such as deer flies,

black flies, and punkies {CuliGoides). When applied to the skin

or clothing (fig. 20), it lasts longer

than any other material. It is safe

to use on the skin and clothing

when applied according to instructions. However, it may cause

slight irritation if it gets into the

eyes. It has desirable cosmetic

properties; it dries quickly on the

skin to an almost invisible film, is

not oily, and is almost odorless.

Diethyltoluamide is more resistant

to removal by wiping and is more
34 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

PiGUBE 20.—Testing stockings treated

with repellents against mosquitoes at

Anchorage.

persistent under sweating conditions than other repellents. It is

also less easily removed when the

skin is rinsed with water.

Insecticides

Before the newer organic insecticides became available, adult mosquitoes in buildings were destroyed

with pyrethrum space sprays. The

effectiveness of the newer materials and their low cost make it possible to utilize space sprays both

in buildings and over large outdoor

areas. In addition, many of these

newer insecticides will kill insects

when they are applied as residual

treatments to surfaces where the

insects rest.

Space treatments.—Space treatments may be made with sprays

or aerosols (16,59). Droplets with

diameters up to 40 microns have

been classed as aerosols and those

with diameters ranging from this

size to 400 microns have been considered to be sprays. In addition

to the newer organic materials such

as DDT, methoxychlor, and lindane

{62), many sprays may contain

pyrethrum, allethrin, or some of

the thiocyanates. Malathion is also

being used in aerosols, particularly

in areas where resistance has developed to the chlorinated hydrocarbons.

Perhaps the most widely known

indoor space treatment other than

that applied by the hand-pressure

sprayer is that produced by the

aerosol bomb. A few seconds' application will kill the mosquitoes

in an ordinary-sized room or tent.

If there is no wind, temporary relief can also be obtained outdoors

by releasing the aerosol as one

walks in swaths over the area. The

directions on the container should

be followed.

Mist blowers and large fog machines are used to control adult

mosquitoes over large areas. Various smaller mobile units for pneumatic spraying or production of

aerosol fog have been found useful

m,15,17,7J^,92,93). Specialized

mist-producing equipment built for

use around camps in Alaska is

shown in figures 21 and 22 {113,

lU).

The large aerosol machines may

be supplemented by smaller equipment attached to the exhaust manifold of motor vehicles {16, 22, U,

78, 92, 93). The jeep exhaust

aerosol is relatively simple and inexpensive to build and attach to a

jeep. Temporary relief from mosquitoes can visually be obtained

around campsites and other small

localized areas with this equipment.

In this unit the oil solution containing the insecticide is introduced

into the exhaust system, where it

is broken up into aerosol particles.

Five percent of DDT in diesel oil

is commonly used.

The exhaust aerosol, which was

developed by the National Research

Council {86), has been modified by

Jones and Holten {78) to reduce

the back pressure on the engine and

increase the atomization of the
THE MOSQUITOES OF ALASKA 35

'^tsrJSÄ

FIGURE 21.—Wenpel trailer equipped with compressor and insecticide tank, releasing

aerosol for protection of personnel at Umiat. (Photograph by Charles Wilson.)

FIGURE 22.—Small encampment on arctic slope protected by a series of aerosolproducing units consisting of fruit-jar insecticide containers and nozzles attached

at intervals to a compressed-air line. (Photograph by Charles Wilson.)
36 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

insecticide solution. Tlie modified

unit is also easier to clean. The

jeep should be operated at a speed

of about 5 miles per hour in compound low gear for most efficient

aerosol production. The following

illustrations and instructions for

fabrication and installation of this

unit are given with pennission of

the authors:

Commercial bids for the manufacture

of one of the units were about $.30.00,

while the cost to construct the unit in

our shop was about $6.00 for labor and

$5.00 for materials, a total of $11.00.

The list of materials required is as

follows :

One Vs" black pipe tee

One Vs ' ' black pipe plug

One brass 14 " PiP« to 14 " tubing

connection

One piece %" copper tubing 5" long

One piece li/4" black pipe 2%" long,

threaded one end

One 11/4" black pipe coupling

In addition to these materials for the

venturi unit itself, the following are

needed for completing the installation

on the jeep :

4%' of Vi" id. copper tubing for feed

line

Four brass %" pipe to %" tubing

connections

One 114" black pipe nipple 10" long

threaded both ends

One 1%" black pipe tee

One brass 14" globe valve

One storage tank

The measurements [fig. 23] of this unit

are the same as those given in the National Defense Research Committee report ( 1945 ) except for the following :

1. The throat of the venturi was

increased from %6" i-d. to %" i.d. to

eliminate excess back pressure. Measured back pressure was obtained at any

engine speed which would allow eflScient

1/8" pipe plug

1/8" pipe tee reamed

and tapped at feed

and jet end to 1/4"

1 1/4" I.D. pipe coupling

1/4" pipe to 1/4" tubing

connector

Jeep exhaust venturi

-AerosolOpen end of pipe coupling

is connected to 10" long

1 1/4" pipe nipple extension from 1 1/4" tee

brazed in exhaust pipe

4" below manifold. Black

areas at joints indicate

brazing. All threaded

joints coated with oilgraphite irtixture so unit

may be easily disassembled

for cleaning.

1/4" I.D. copper tubing

from insecticide tank

connects here

1/4" I.D. pipe nipple

3" long

1/4" I.D. pipe nipple

threaded only one end

2" long

1/4" I.D. copper tubing to

be cut off to discharge

insecticide at start of

venturi throat

Threaded pipe section

brazed on for capping

purposes

FIGURE 23.—Diagram of a jeep exhaust venturi aerosol.

PN-8S0

(From Jones and Holten 78.)
THE MOSQUITOES OF ALASKA 37

FIGURE 24.—Jeep exhaust venturi aerosol :

A, Closeup view of mounted unit; B,

unit in operation.

operation of the exhaust venturi generator.

2. The single-size tube assembly used

[fig. 24, A] was substituted for the

original curved two-size jet tube so that

it could be dismantled and reamed free of

carbon with a minimum of tools and time.

3. The fixed mounting in lieu of the

flexible mounting permits constant availability and ease of operation. The control valve on the driver's side of the

jeep allows one man to both drive and

operate the venturi.

The convergent and divergent sections

of the venturi can most satisfactorily

be formed on a mandrel turned to proper

size.

When installing the unit, the exhaust

pipe of the vehicle is cut four inches

below the manifold and a section of the

exhaust pipe long enough to allow the

insertion of a tee joint is removed. A

IM" black pipe tee is then brazed into

this opening. A IVi" pipe nipple 10"

long extends from the tee joint and the

venturi unit is screwed onto this extension. Black pipe is used rather than

galvanized for ease of brazing parts.

An oil and graphite mixture is used to

coat all threaded joints so that they may

be broken easily even after heating, when

the unit must be dismantled for cleaning. The supply tank may be of any

size, shape, and capacity, but should be

placed so that it is at least 18" to 24"

above the venturi throat. The tank is

normally placed in the rear of the jeep

above the fender well.

In operation [fig. 24, ß], the unit may

be controlled to produce a dry fog

(aerosol) or a wet fog (mist) by the

gravity feed line control valve which

controls the volume of insecticide introduced into the venturi. The jeep exhaust

pipe is plugged with a I14" pipe plug

when the venturi is in operation. A

IVi" i.d. pipe coupling is brazed onto

the exhaust pipe to take this plug. When

the venturi is not in use, it is capped

with a %" pipe cap, and the exhaust

pipe unplugged.

Although the aerosol treatments

can reduce mosquito annoyance in

urban or rural communities, the

effect of a single treatment seldom

lasts more than a few hours. The

length of time will depend on the

area treated and the abundance and

flight habits of the mosquitoes, and

best results will always be obtained

when the applications are made by

experienced operators.

Airplane applications of DDT

spray (fig. 25) {I4.) have proved

the most economical method of controlling adult mosquitoes in or near

the larger urban centers of Alaska.

The formulation most often used

contains 20 percent of DDT in fuel

oil with at least 20 percent of an

auxiliary solvent. The dosage is

0.1 to 0.2 pound of DDT or 1/2 to 1

pint of spray per acre.

"Wliere mosquitoes have become

resistant to DDT, other insecticides

are being used, such as lindane,

chlordane, aldrin, and dieldrin,

which are especially toxic to fish.

No insecticide sprays should be used

over large bodies of water where

they are hazardous to fish. All aircraft spraying should be directed by

specialists and trained pilots.

Residual sprays.—Many of the

organic insecticides, including

DJDT, will remain effective for

several months when applied to

the interior surface of buildings

and for a week or more when

applied to the exterior of buildings

or to vegetation. Mosquitoes that
38 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

FiGüEE 25.—Spraying near Fairbanks with one-half pint of 20-percent DDT per

acre. Picture taken at midnight.

rest on the treated surfaces will be

killed by the residues.

DDT residual sprays for use on

buildings should contain 5 percent

of DDT either in oil solution or in

emulsion. The best results are obtained if all the walls and ceilings

are treated. The rate of api^lication

should be about 1 gallon per 1,000

square feet. If the surface is not

particularly absorptive, reapplication may be necessary. In Alaska

an application at the beginning of

each mosquito season should be

adequate.

Annoyance around buildings can

be further reduced by spraying all

vegetation to a height of about 10

feet (iJ). The wider the treated

band, the better the results, for the

mosquitoes will not be killed until

they rest on the sprayed vegetation.

During periods of flight activity

sucli treatments may provide poor

protection, since infiltrating mosquitoes may cause considerable annoyance before they are killed.

Good control of the Aedes species

common in Alaska was obtained in

the Cascade Range of Oregon for

10 to 45 days witli residual treatments of DDT at 2 to 6 pounds per

acre on plots larger than one-Iialf

acre. Lindane at 3 pounds per acre

gave control equal to that obtained

with 4 pounds of DDT [69). In

order to avoid damage to vegetation, wettable powders or oil emulsions should be used rather than oil

solutions.

Insecticides are poisonous.

When handling or mixing concentrated insecticides, avoid spilling

them on the skin and keep them

out of the eyes, nose, and mouth.

If any is spilled on the skin, wash

it off immediately. If any is

spilled on the clothing, change it

immediately. Try to keep the

spray away from the eyes, nose,

and mouth when it is being applied. Wash exposed skin surfaces with soap and water and

change the clothing after using

insecticides. Follow the precautions on the container labels.

The extremely poisonous organic
THE MOSQUITOES OF ALASKA 39

phosphorus insecticides such as

parathion and methyl parathion

should be handled only by a person who is thoroughly familiar

with their hazards.

CONTROL OF RESISTANT

MOSQUITOES

Resistance to insecticides has

developed in many insects in many

parts of the world. In some communities in California (5J^),

Florida {25, 79), and Oregon (28),

mosquitoes have developed a high

resistance to DDT and other chlorinated hydrocarljon insecticides.

Organic phosphorus insecticides

have given control \\\ tliese communities {J^% 63). Parathion has been

efl'ective in one such area for 8 years,

but partial resistance to malathion

has developed in a similar area in

California {62) after 21/^ years. In

Alaska resistance is expected to develop very slowly, because only one

generation is produced annually by

the Aedes species, wliicli comprise

the major pests.

Technique for Mosquito Collection and Survey

Specimens that are to be prepared for study in the laboratory

or that are to be preserved for a reference collection must receive special attention if they are to serve

their purpose.

Larvae and pupae.—A white enamel dipper with a smooth stick

about 3 feet long inserted in the

handle (fig. 26, A) is best for collecting larvae and pupae. Remove

them from the dipper with an eye

dropper or pipette (fig. 26, 0).

As the tip of an ordinary eye

dropper is too small for sucking

in full-grown mosquito larvae and

the pupae, break it off to enlarge

the opening.

The larvae and pupae can be

reared in the laboratory. Since in

general only the mature larvae

(fourth instar) can be identified,

rear the young larvae to the fourth

instar. A careful worker will rear

the larvae individually and will

save the larval and pupal skins so

that they can be associated with the

adults.

In the field, preserve the larvae

in 70- to 80-percent alcohol. Prevent undue dilution of the alcohol

with water; as a precautionary

measure change the alcohol after a

few hours. Fill the vials (fig. 26,

B) with liquid to prevent sloshing

and consequent damage to the larvae. Handle the larvae carefully, as

the spines and hairs necessary for

identification are easily broken off.

Specimens retain their shape better

if killed in hot water (lOO^-lSO"

F. ) and then transferred to alcohol.

A i-ounce jar or larger (fig. 26, D)

may be used for carrying live larvae. Injury to larvae will be

avoided if the jar is filled to the

brim with water.

To make permanent preparations of larvae or larval and pupal

skins, remove them from the alcohol in which they have been preserved and mount them on microscope slides. The larval mounts are

more satisfactory if the larvae are

then punctured with a needle.

Place the punctured larvae or skins

in Cellosolve for a few minutes

and then in a drop of balsam or

euparal on a slide, orient them, and

cover with a glass coverslip. The

abdomen may be cut before the

balsam is applied, so that the anal

segment and siphon can be turned

on the side. Such specimens, if

carefully prepared, will last indefinitely.

Adults.—ThB most useful specimens of adult mosquitoes are pre-
AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

PN-833

FIGURE 26.—Mosquito-collecting equipment: A, Dipper; B, vial; C, wide-mouthed

pipette ; D, jar for carrying live larvae ; E, killing bottle ; F, paper funnel ; G, live

tube; H, aspirator, straight-tube type; /, lantern chimney cage; J, pill boxes; K

and L, aspirator, showing construction details.
THE MOSQUITOES OF ALASKA 41

pared as soon as they are killed or

collected. Do not kill those reared

in the laboratory for 24 hours after

they emerge as adults to allow

them time to harden.

The most useful killing bottle

(fig. 26, E) is a chloroform tube.

Fill a strong glass tube to tlie deptli

of about one-half inch with cut

rubber bands or other small pieces

of rubber. Pour in enough chloroform to cover the rubber pieces and

close the tube tightly with a cork.

When the chloroform has been absorbed by the rubber, tamp in a plug

of cotton. On top of the cotton

place several disks of blotting paper

cut to fit the tube tightly. Such

a bottle should last several days before it needs recharging with chloroform, provided it is kept tightly

corked when not in use. Plac« a

few strips of soft paper, i/^ to 14

inch wide, in the tube to prevent the

mosquitoes from being unduly

rubbed. To increase the number of

mosquitoes that can be caught, place

a short paper funnel (fig. 26, F) in

the mouth of the killing bottle.

This funnel acts as a barrier to prevent the escape of the specimens before they are killed and to reduce

the loss of chloroform fumes.

Another hand-collection device, is

a suction tube, or aspirator (fig. 26,

Z), made out of a glass or clear

plastic tube about three-fourths

inch in diameter and 5 to 6 inches

long. Intake and outlet tubes inserted through the rubber stopper

should be copper, as glass tubes are

too easily broken. Fasten bolting

cloth or fine mesh copper screening

over the inside aperture to the outlet tube. Mosquitoes can then be

sucked into the aspirator tube and

blown into the killing bottle. Another type of aspirator, as shown in

figure 26, K, is better for handling

adults that are to be transferred to

a live jar, or lantern chimney cage

(fig. 26,7).

After collecting a few specimens

in the killing bottle, transfer them

to a small container sucli as a pasteboard pill box. The pill box (fig.

26, J) should contain two pieces

of soft tissue paper between two

layers of cotton. Place the mosquitoes between tlie layers of tissue.

Witliout the tissue paper the tarsal

claws may cling to the strands of

cotton and may be broken. Handle

the specimens carefully, as scales

and hairs that are important for

identification are easily rubbed off.

In the field, pin the best specimens

as tliey are caught.

Mosquitoes may be kept alive in

a large-diameter glass tube or a vial

open at both ends (fig. 26, G).

Cover the top with bobbinet and

insert in tlie bottom a cork, in which

a capillary tube is inserted for furnishing water. Place a freshly cut

raisin or wad of cotton saturated

with sweetened water on top of the

bobbinet for food. A glass lantern

chimney (fig. 26, /) may be similarly equipped as a container for

a large number of adults. Generally one end is covered with a

sheet of tliin rubber. A i/2-inch

slit in the rubber permits the collector to add adults to the container

with an aspirator (fig. 26, H).

Adults that are to be retained

in ijemianent collections are best

mounted on a minuten pin stuck into a small square piece of cork,

through which is passed a larger

pin. Thrust the tip of the minuten

pin through the underside of the

thorax of the mosquito, but not far

enough to protmde through the

mesonotum. The No. 3 entomological pin is generally the best size

for holding the cork.

Label the mounted specimens

carefully and pin them in a tight

insect box. Protect the stored

specimens from insect pests and

dampness. Place ñake naphthalene

or paradichlorobenzene in a perforated container and fasten the

container securely in one corner of
42 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

the insect box to prevent damage

from insect intruders. Renew these

repellents occasionally.

Älany of the northern Aedes mosquitoes are difficult to identify, and

often only the males can be accurately identified. Mounts of the

male genitalia for study purposes

may be made as described for mosquito larvae. The genitalia should

first be cleared in potassium

hydroxide.

Identification of Species

The principal characters distinguishing the different species are

the shape, size, coloration, and

scaling of the different body parts.

A binocular dissecting microscope

with magnifications up to about

85 X is necessary for satisfactory

examination. For examining larval parts and slide mounts of male

terminalia, a compound microscope with a magnification up to

iOOX is necessary. A bright spotlight is required when high magnifications are used.

In the field a good hand lens with

a magnification of 10 or 15 X is

satisfactory for provisional identifications. After some experience

one will be able to identify some of

the species with a hand lens or even

with the naked eye.

Misidentification of mosquitoes

may cause serious confusion. A

few specimens that have been correctly identified will be helpful for

comparison. If in doubt about the

identity of specimens, send them to

a specialist with the request that

they be named and returned. They

may be identified if sent to the Entomology Research Division or to

some of the State universities and

agricultural experiment stations.

Keys and Notes for Identification

The 27 species of mosquitoes

found in Alaska belong to 4 genera.

Keys for their determination are

based on characters given in the

literature and on others that have

been added. The characters used

by Vockeroth {109) and by Beckel

[11) in keys to females present in

Canada have been particularly useful in separating species found in

Alaska. The spines on the anal

plate described by Frolme {35)

have sometimes been utilized in the

larval keys. Only the more important taxonomic data for each

species are included here, and only

synonyms of recent date are given.

The characters used for identifying

the Aedes species are shown in

figures 27 to 32.

COiTAL CELL •uaCoaTAL CELL

FIGURE 27.—Wing of Aeáes mosquito, illustrating venation (modified from Boss and

Roberts 95). H-v, humeral cross vein ; C, costa ; Se, subcosta ; Pi, petiole of vein 2 ;

1, 2.1, 2.2, 3, 4.1, 4.2, 5.1, 5.2, and 6, longitudinal veins and their branches.
THE MOSQUITOES OF ALASKA 43

Scutellum

occiput

FIGURE 28.—Lateral view of mosquito head and thorax, hs, hypostigial spot of scales

and pcs, postcoxal scale patch. Sclerites of thorax : 1, Anterior pronotum ; 2, proepisternum ; 3, postpronotum ; 4, mesanepisternum ; 5, prealar area ; 6, sternopleuron ; 7, mesepimeron : 8, nietanepistemum ; 9, metasternum ; 10, metepimeron ;

11, postnotum : 12, meron. Setae: apn, anterior pronotal ; ps, proepisternal ; ppn,

postpronotal ; sp, spiracular ; psp, postspiracular ; pa, prealar; stp, sternopleural ;

utne, upper mesepimeral ; Une, lower mesepimeral.

FIGURE 29.—Male genitalia of Aedes, dorsal view, showing parts : SP, sidepiece ;

Sc, scale; BL, basal lobe; Mes, mesosome; L9, lobe of ninth tergite; 9T,

ninth tergite ; S, spine of clasper ; CL,

clasper ; AL, apical lobe ; F, filament of

claspette; Clsp, claspette; IOS, tenth

sternite ; P, paramere ; BP, basal plate.
44 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

FIGURE 30.—A, Aedes impUeatus, side of thorax showing scaling; B, Aedes communis,

same.

PMM

FIGURE 31.—Ventral view of thorax of

Aedes. OC, occiput; APN, anterior

pronotum ; PPN, posterior pronotum ;

PB8, probasisternum ; 8PB, sternopleural bridge ; PMM, postmetasternal

membrane.

H£AD HAIRS

LOWER.

UPPER.

ANTENNAL TUFT

\ANTEANTENNAL

TUFT

HEAD

THORAX

ABDOMEN

LATERAL COMB

OF 8TH SEGMENT

ANAL GILLS

DORSAL TUFT- VENTRAL TUFT

PN-83e

FIGURE 32.—Larval characters used in

identifying mosquito larvae of Alaska.

KEYS TO GENERA

Adults

1. Scutellum trilobed with marginal setae on lobes onh'; palpi in females

much shorter than proboscis 2

Scutellum crescent shaped with marginal setae evenly distributed;

palpi of males and females almost as long as proboscis.. Anopheles {earlei, p. 77)

2. Postspiracular bristles present Aedes

Postspiracular bristles absent 3

3. Spiracular bristles present Culiseta

Spiracular bristles absent Culex {territans, p. 79)
THE MOSQUITOES OF ALASKA 45

Larvae

1. Eighthsegment without dorsal siphon or respiratory tube,. Anopheles (earlei p 77)

Eighth segment with elongated siphon or respiratory tube.,. 2

2. Air tube with siphonal tufts at base " " Culiseta

Air tube with tufts near or beyond middle ' 3

3. Air tube with two or more pairs of tufts extending to end of" tube

,. . , -^u 1 . , , Cidex (territans, p. 79)

Air tube with only one pair of tufts Aedes

GENUS AEDES MEIGEN

KEYS TO SPECIESi

Adults

1. Tarsal segments ringed with white 2

Tarsal segments not ringed with white "." 7

2. Tarsi with white rings at both ends of segments canadensis, p. 48

Tarsi with white rings at base of segments only 3

3. Abdomen with dull-yellow scales and irregular dark-scaled areas or

completely yellow scaled; tarsal claw as in figure 50, B flavescens, p. 58

Abdomen dark scaled with white or gray dorsal bands 4

4. Tarsal claw large, sharply bent, and nearly parallel to long tooth

(fig. 46, B) excrucians, p. 55

Tarsal claw smaller, not sharply bent, and not parallel to shorter

tooth 5

5. Mesepimeral bristles absent; tarsal claw as in figure 66, B riparius, p. 68

Mesepimeral bristles usually present; tarsal claw as in figure 48, ß__ 6

6. Lower mesepimeral bristles three or more; torus with or without

scales on dorsal half Stimulans, p. 69

Lower mesepimeral bristles none to four but rarely more than two;

torus with white scales on dorsal half fitchii, p. 56

7. Abdomen without basal white bands or with some narrow or incomplete ones 8

Abdomen with basal white bands 10

8. Mesonotum reddish brown; fore coxae with central area of brown

scales cinereus, p. 50

Mesonotum with narrow median brown stripes; fore coxae with

white scales only 9

9. Sternopleuron with 5 to 10 setae, of which a vertical line of one to

four is just anterior to lower edge of mesepimeron; torus with

integument dark brown or black dedicus, p. 53

Sternopleuron with 12 to 20 setae, of which a patch of 7 to 12 is

anterior to and below lower edge of mesepimeron; torus with

integument of outer side yellow to light brown diantaeus, p. 54

10. Postcoxal scales present 11

Postcoxal scales absent 18

11. Postpronotum with setae scattered over posterior half 12

Postpronotum with setae in single or irregular double row along

posterior margin 13

12. Tarsal claws sharply bent with slender tooth nearly parallel and onehalf length of claw (fig. 53, B) impiger, p. 60

Tarsal claw elongate with blunt tooth not parallel with claw (fig.

59, B) nigripes, p. 64

13. Posterior part of probasisternum with many white scales -. 14

Posterior part of probasisternum without or rarely with few white

opo Ipe J-"

14. Mesonotum yellow or rarely gray with dark-brown stripes narrowed

at back and extending to scutellum piomps, p. 65

Mesonotum brown or occasionally with faint dark markings ,, . ,

hexodontus ("tundra variety), p. 59

15. Sternopleuron with scales extending to frontal border 16

Sternopleuron with scales not extending to frontal border 17
46 AGB. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

16. Mesonotum yellowish to light golden brown with dark-brown

lines punclor, p. 67; aboriginis, p. 47

Mesonotum brown or occasionally with faint dark markings

punctor ("tundra" variety), p. 67

17. Wings with scattered line of white scales extending from base of costa

to humeral cross vein cataphylla, p. 49

Wings dark scaled or with patch of white scales at base of costa

implicatus," p. 61

18. Sternopleuron with scales extending to frontal border communis, p. 51

Sternopleuron with scales not extending to frontal border 19

19. Mesonotum yellowish brown with median brown stripes; wings with

pale scales extending from base of costa to humeral vein puUatus, p. 66

Mesonotum bronzy brown with gray scales around margins and

rarely with darker markings centrally; wings dark scaled or with

small patch of pale scales at base of costa intrudens, p. 62

Larvae

1. Pectén of air tube with one or more of distal teeth more widely spaced 2

Pectén teeth of air tube equally spaced 10

2. Anal segment ringed by plate nigripes, p. 64

Anal segment not ringed by plate 3

.3. Hair tuft of air tube distinctly basal of last pectén tooth cataphylla, p. 49

Hair tuft >-f air tube even with or distad of last pectén tooth 4

4. Antennae longer than head diantaeus, p. 54

Antennae shorter than head 5

5. Apical setae of lateral valves (i.e., triangular flaps at apex of tube)

hook shaped, as long as longest pectén tooth excrucians, p. 55

Apical setae of air-tube valves barely discernible, not longer than

shortest pectén tooth 6

6. Upper and lower head hairs single or double 7

Upper head hairs three or more branched, lower two or more

branched 8

7. Antennae not longer than anal segment riparius, p. 6S

Antennae at least one-fourth longer than anal segment decticus, p. 53

8. Upper head hairs two or three, lower double flavescens (in part), p. 58

Upper head hairs usually four or more, lower two or three 9

9. Tuft of air tube with five to seven hairs intrudens, p. 62

Tuft of air tube with two or three hairs cinereus, p. 50

10. Anal segment ringed by plate or very narrowly open ventrally 11

Anal segment not ringed by plate, broad opening ventrally 12

11. Comb of eighth segment a row of 5 to 9 or rarelv 10 scales; anal

plate closed ' hexodontus, p. 59

Comb of 10 to 19 scales; anal segment narrowh' open or closed punctor, p. 67

12. Both pairs of head hairs single or occasionally with one or two hairs

double 13

Both pairs of head hairs not single and at least one pair multiple 15

13. Comb on eighth segment of 40 or more scales communis, p. 51

Comb on eighth segment of less than 30 scales 14

14. Comb on eighth segment of 8 to 16 thornlike scales, lateraî spinales

less than half as long as apical spine impiger, p. 60

Comb of 15 to 25 blunt scales, lateral spinules nearly as long as

apical spine implicatus,p.%\

15. Apical setae of air-tube valves hook shaped and as long as lateral

valve , fitchii, p. 56

Apical setae of air-tube valves inconspicuous, not so long as lateral

valve 16

16. Air tube with pectén teeth on basal one-third or occasionally slightly

farther; anal gills usually twice length of anal segment; (spines

on apex of anal plate long and slender, fig. 63) pullatus, p. 66

Air tube with pectén extending nearly one-half length of tube; anal

gills seldom twice length of anal segment 17

17. Comb on eighth segment with 60 or more scales; air tube about

2U X 1 (spines on apex of anal plate short and slender, fig. 61). pionips, p. 65

Comb on eighth segment with less than 40 scales; air tube about

3 X 1 18

' About 10 percent of the females of this species have a few scales extending to the

frontal border of the sternopleuron.
THE MOSQUITOES OF ALASKA 47

18. Comb scales thornlike; apical spine more than twice as long as any

lateral spinule flavescens (in part), p. 58

Comb scales acute apically but not thornlike; apical spine less than

twice as long as lateral spinules ig

19. Upper head hairs si.x to seven, lower four to five 'canadensis p 48

Upper head hairs three to four, lower two to four ' 20

20. Anal segment longer than wide; mesothoracic hair Ño. 1 double or

triple Stimulans p 69

Anal segment about as long as wide; mesothoracic hair Ño. 1 single '

aboriginis, p. 47

Male Genitalia

1. Glasper inserted before apex of sidepiece; unequally bifurcate at

base cinereus, p. 50

Clasper not inserted before apex of sidepiece; not branched at base. 2

2. Basal lobe without spines 3

Basal lobe with spines 5

3. Filament of claspette narrow and of approximately equal width, canadensis, p. 48

Filament of claspette expanded along one margin 4

4. Filament of claspette with one side roundly expanded at base___ nigripes, p. 64

Filament of claspette with one side expanded to sharp point at base

excrucians, p. 55

5. Basal lobe with one spine 6

Basal lobe with two or more spines 14

6. Apical lobe with short appressed setae

aboriginis, p. 47; hexodontus, p. 59; punctor, p. 67

Apical lobe with long hairs or nearly bare 7

7. Basal lobe extending almost to apical lobe flavescens, p. 58

Basal lobe a small area at base of sidepiece 8

8. Apical lobe of sidepiece nearly bare 9

Apical lobe distinctly setose 10

9. Filament of claspette expanded into sharp projection near base

implicatus, p. 61

Filament of claspette expanded in gradual curve near base caiaphylla, p. 49

10. Filament of claspette sickle shaped with small notch at base fitchii, p. 56

Filament of claspette not notched at base 11

11. Basal lobe rounded 12

Basal lobe cone shaped or wedge shaped 13

12. Filament of claspette expanded to its maximum width at base

commiinis,^" p. 51; pionips, p. 65

Filament of claspette expanded to its maximum width near middle

Stimulans, p. 69

13. Basal lobe projecting in cone shape at right angles to sidepiece. _ riparius, p. 68

Basal lobe evenly sloped to its maximum width at basal edge impiger, p. 60

14. Apical lobe with dense tuft of long hairs 15

Apical lobe without tuft of hairs 16

15. Apical lobe conical, well developed; claspette stem with sharp angle

near apex diantaeus, p. 54

Apical lobe flattened, oval; claspette stem with rounded shoulder

near apex decticus, p. 53

16. Claspette with sharp angular projection ending in stout setae at

middle inirudens, p. 62

Claspette with rounded angle at middle pullatus, p. 66

'»Postcoxal scale patch present on male pionips and absent on communis.

Aedes aboriginis Dyar row along posterior margin. PostAeäes aboriginis Dyar, Insecutor Insci- coxal scales present. Sternotiae Menstruas 5: 99. 1917. pleuron with scales extending to

Female.-Mesonotum yellowish frontal border. Scutelhim with

to light golden brown with paired jeHow or bronzy bristles. Prodark brown stripes and posterior basisternum without white scales on

half lines. Postpronotum with posterior part. Lower mesepimeral

setae in single or irregular double bristles one or two. Abdomen black

551&10 0—61 4
48 AGR. HANDBOOK 18 2, U.S. DEPT. OF AGRICULTURE

with basal white bands widening at

sides. Wings dark scaled in about

95 percent of specimens. Legs

black.

Male genitalia, (fig. 33).—Sidepieces three times as long as broad;

apical lobe long and rounded with

short curved setae ; basal lobe flatly

conical with numerous setae and

long curving spine near base. Claspette pilose, slightly curved, and

expanded near middle; filament

shorter than stem, slightly expanded at middle, and terminating

in blunt curved point.

Larva.—Antennae sparsely

spined. Head hairs, upper usually

three to four and lower two to four.

Mesothoracic hair No. 1 single. Lateral abdominal hairs one to two

long hairs. Comb on eighth segment with about 30 scales in patch.

Air tube about 3X1; pectén fine

and even and not reachmg middle,

followed by four to six large hairs ;

apical setae not so long as lateral

valve. Anal segment about as long

FIGURE 33.—Aedes aboriginis male genitalia.

PN-841

FIGURE 34.—Aedes canadensis male

genitalia.

as wide, anal plate extending to

near ventral line; anal gills pointed

and longer than segment.

Bionomics.—This species has

been recorded from several localities in the Panhandle (map 9).

Larvae were collected in May, June,

and July in roadside borrow pits

that were devoid of vegetation

(Frohne and Sleeper 4^). Nothing

further is known of the species'

habits or behavior in Alaska.

Aedes canadensis (Theobald)

Culex canadensis Theobald, Monog. of

Culicidae of World, v. 2, p. 3. 1901.

Female.—Mesonotum reddish

brown with pale-yellow scales

around margins. Abdomen black

without basal white bands or with

narrow indistinct ones; sides with

triangular white spots. Wing

scales all dark. Legs black; hind

and midtarsal segments apically

and basally w^hite banded; fore

tarsus banded on first and second

segments ; last segment of hind leg

entirely white scaled.

Male genitalia (fig. 34).—Sidepieces slightly more than twice as

long as wide; apical lobe large,

low, and broadly rounded with short

bladelike setae; basal lobe long,
THE MOSQUITOES OF ALASKA 49

PN-842

FiGUEE 35.—Aedes canadensis larva.

with many short setae. Claspette

cylindrical and setose, larger seta

before apex; filament narrow, linear, pointed, and slightly shorter

than stem.

Larva (fig. 35).—Antennae spinöse. Upper head hairs six to

seven, lower four to five. Lateral

abdomen hairs usually double on

first to fifth segments and single on

sixth. Comb on eighth segment

with 25 to 40 scales in irregular

patch. Air tube 3 X 1 ; pectén even,

reaching beyond one-third of tube,

followed closely by tuft of four to

six medium hairs; apical setae

shorter than lateral valve. Anal

segment longer than wide, not

ringed by plate; anal gills pointed

and about as long as segment.

Bionomics.—Craig and Pienkowski {21) found canadensis near

Circle, and also they reported it to

be the dominant pest mosquito in

late July of 1955 at a locality near

Eielson Air Force Base. These are

the only records for the species from

Alaska (map 9). They are of

special interest since the area between Eielson and Fairbanks was

surveyed by the Alaska Insect Control Project in 1947 and studied intensively during the entire spring

and summer of 1948. It is hardly

conceivable that such an easily recognized species could have been

missed ; more likely this is further

evidence of the year-to-year instability of the mosquito population in

centralAlaska. No larvae have been

collected in Alaska. In the United

States and Canada larvae develop

in temporary or semipei'manent,

shaded, woodland pools containing

fallen leaves.

Aedes cataphylla Dyar

Aedes cataphylla Dyar, Insecutor Inscitiae Menstruus 4 : 86. 1916.

Female.—M esonotum gray

around sides with golden-brown

scales in middle, which sometimes

show faint dark lines. PostpronotiuTi with setae in single or irregular

double row along posterior margin.

Postcoxal scales present. Stemopleuron with scales not extending to

frontal border. Probasisternum

without white scales on posterior

part. Lower mesepimeral bristles

two to seven. Hypostigial spot of

scales usually present. Abdomen

black with basal segmental white

bands. Wing scales dark with

scattered pale scales extending from

base of costa to humeral cross vein.

Legs black with mixture of pale

scales; tarsi mostly black.

3iate genitalia (fig. 36).—Sidepieces about three times as long as

wide; apical lobe small, elongated,

and narrowly attached with few

short spines; basal lobe small, elevated into transverse ridge at base

with row of long setae and slender

spine at margin. Claspette lightly

hirsute except at apex ; filament expanded in gradual curvee near

middle.

Larva (fig. 37).—Both pairs of

head hairs single. Comb on eighth

segment in two irregular rows.

Air tube about 3X1; evenly spaced
50 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

FiGUEE 36.—Aedes cataphylla male

genitalia.

pectén teeth to hair tuft and three

to five widely spaced teeth beyond.

Anal segment with plate extending

well down sides; anal gills as long

or longer than segment.

Bionomics.—This is a less common species found in central Alaska

from Anchorage north to Fairbanks and west to Teller (map 7).

Larvae occur in shallow temporary

or semipermanent pools in Carex or

Calœmagrostis marshes. During

1948 larvae were collected at nine

localities during the last week of

May and at one locality near Anchorage on September 15.

Aedes einereus Meigen

Aedes cinereus Meigen, System. Beschr.

Bur. Zweifl. Ins., v. 1, p. 13. 1818.

Female.—Mesonotum clothed

with reddish-brown scales. Postcoxal scale patch present. Probasisternum bare. Lower mesepimeral

bristles absent. Abdomen black

without white bands or with narrow partial or complete ones;

lateral spots usually joined to form

line. Wing scales dark. Legs dark

brown ; coxa of front leg with white

PN-844

FIGURE 37.—Aedes cataphylla larva.

scales and central patch of brown

scales on anterior surface.

Male genitalia (fig. 38).—Sidepieces twice as long as wide, broad,

and sharply tapered to densely

spined apex. Clasper subapically

inserted, with forked arras of

unequal length. Claspette two

PN-846

FiGUBE 38.—Aedes cinereus male genitalia.
THE MOSQUITOES OF ALASKA 51

branched with three spines at apex

of each branch.

Larva (fig. 39).—Antennae

shorter than head. Upper head

hairs tliree to seven, lower two to

five, tufts set close together.

Lateral abdominal hairs double on

first and second segment, single and

long on third to sixth. Comb on

eighth segment with 10 to 12

slender pointed scales. Air tube

about 3 X 1 ; pectén extending past

middle of tube, last three or four

teeth detached, tuft with two or

three hairs; apical setae very short.

Anal segment longer than wide,

not ringed by plate ; gills very long

and lanceolate.

Bionomics.—This species has

been taken in largest nmnbers near

Fairbanks, but larvae have also

PN-846

FIGURE 39.—Aedes ciñerens larva.

been collected at. Anchorage and

Valdez. The species has also been

taken in the timdra zone at Nome

and Kotzebue (map 4). Partially

shaded, shallow, semipennanent

pools in Carex and Calamagrostis

marshes are favored liabitats for

the larvae. At Fairbanks in 1948

fourth-stage larvae were collected

from May 26 througli July 15 and

were most numerous about June 3.

No fourth-stage larvae were taken

at Anchorage until June 20, but

they persisted until October 8 and

were most numerous on September

15. The species is easily recognized in the adult stage and has not

been observed to be a serious pest

in Alaska.

Aedes communis (DeGeer)

Ctilex communis DeGeer, Mem. Servir

Hist. Insectes, v. 6, p. 316, figs. 2

and 5. 1776.

Aedes prolixus Dyar, Insecutor Inscitiae

Menstruus 10: 2. 1922.

Female.—Mesonotum dull yellow

or gray scaled with narrow pale

median line separating paired darkbrown lines and with posterior

brown half lines. Coloration variable and may be brown scaled cen-.

trally with mixture of pale scales

and border of grayish-yellow scales.

Postpronotum with setae in single

or irregular double row. Postcoxal

scale patch absent. Sternopleuron

with scales extending to frontal

border (fig. 30, 5, p. 44). Probasisternum with posterior part bare.

Lower mesepimeral bristles two to

five. Abdomen dark brown witli

basal white bands. Wings dark

scaled with patch of two or three to

many pale scales at base of costa.

Legs dark with femora partially

pale.

Male genitalia (fig. 40).—bidepieces about three times as long as

wide; apical lobe large, rounded,

with many long spinelike setae;

basal lobe small, quadrilateral in

outline, partially detached at base,

surface with some small setae.
52 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

FiGUEE 40.—Aedes communis

genitalia.

PN-847

male

several larger curved ones and stout

spine on margin. Claspette lightly

hirsute on basal half, apical half

more slender; filament angularly

expanded to its maximum width

near base.

Larva (fig. 41).—Both pairs of

head hairs single. Lateral abdominal hairs double on first to fifth

segment and single on sixth. Comb

on eighth segment with 50 to 60

scales in triangular patch. Air

tube stout and about 2i/4 X 1 ; pecten evenly spaced to near middle of

tube, tuft of four to six hairs. Anal

segment longer than wide, plate extending only about two-thirds distance down sides, anal gills one to

three times length of anal segment.

Bionomics.—This species is one

of the most common and widely distributed species in Alaska (map 1).

Although it is predominantly a

forest species, it has been taken at

Umiat, Kotzebue, and Teller. Larvae have been found in a wide variety of pools and appear to be able

to live in practically all shallow

pools that are temporary but last

long enough for adult emergence.

Larval population density is often

as high as 500 per dip in Sphagwwrn-heath bog pools. At Anchorage in 1948 peak adult emergence

occurred about May 26 and in reduced numbers continued until the

last of June. Some fourth-stage

larvae were found as late as September 15. At Fairbanks peak

adult emergence was reached about

June 6, and no larvae were found

after June 15.

The frequency of collection and

high population density of pools

producing communis may exaggerate the real importance of this spePN-848

FIGURE 41.—Aedes communis larva.
THE MOSQUITOES OF ALASKA 53

cies. The high population density

tempts the collector to sample such

pools and pay relatively less attention to the vastly more numerous

pools where larvae are often hard to

find and where species other than

Gommunis predominate. This fact

combined with some evidence that

communis may not attack man to

any great extent (Hocking 65)

raises a serious doubt as to the

actual pest importance of the species in Alaska.

Aedes decticus Howard, Dyar,

and Knab

Aedes decticus Howard, Dyar, and Knab,

Mosquitoes of No. and Cent. Amer.,

V. 4. p. 737. 1917.

Aedes pseudodiantaeus Smith, Brooklyn

Ent. See. Bui. 47 :19. 1952.

Female.—Torus with integument

dark brown or black. Occiput with

white and pale-yellow scales, subdorsal patches of dark brown, and

scattered erect dark scales. Mesonotum with median brown stripes

separated by line of pale-yellow

scales; posterior half stripes usually distinct. Postcoxal scale patch

absent. Sternopleuron with 5 to 10

setae, of which a vertical line of 1

to 4 is just anterior to lower edge of

mesepimeron. Lower mesepimeral

bristles absent. Abdomen without

basal white bands or occasionally

with narrow bands on some segments. Wing scales dark. Legs

black with femora partially pale

scaled.

Male genitalia (fig. 42).—Sidepieces more than twice as long as

wide; apical lobe a flattened elongated oval extending almost to

basal lobe, ventral side with large

dense tuft of fine setae; basal lobe

with long spine at its base and two

curved spines on its apical projection. Claspette stout basally and

narrowed beyond curved shoulder

near apex, shoulder bearing small

setae; filament of claspette slender

at base, greatly expanded and ending in two small points.

PN-849

FIGURE 42.—Aedes decticus male genitalia.

Larva (fig. 43).—Antennae almost as long as head with one long

and two short setae at apex, antennae tuft just before middle. Upper and lower head hairs single or

double. Comb on eighth segment of

five to seven scales, each scale with

long median spine and fringe of

basal lateral spinules. Air tube 3 or

4X1; pectén extending to about

middle with one to three detached

teeth, hair tuft even with last

pectén tooth. Anal segment longer

than wide and nearly ringed by

plate.

Bionomics.—This is a forest species recorded from larvae collected

in black spruce bog pools near Fairbanks and from quaking bog pools

in the Copper Kiver Valley near

Chitina (map 9). Larvae taken at

the latter locality were reported by

Frohne and Frohne (4.0) to be associated with Culiseta morsitans,
54 AGR. HANDBOOK 182, U.S. DEPT. OP AGRICULTURE

anterior to and below lower edge of

mesepimeron. Lower mesepimeral

bristles absent. Abdomen without

basal white bands or occasionally

with narrow bands on some of segments. Wing scales dark. Legs

black with femora partially pale

scaled.

Male genitalia (fig. 44).—Sidepieces more than twice as long as

wide; apical lobe conical, well developed, projecting mesally, ventral side at base with dense group

of fine long setae; basal lobe with

long stout spine at its base and two

broad stout spines on its apical projection. Claspette broad basally

and constricted beyond middle to

form sharp angular projection

bearing several small setae; filament greatly expanded and ending

in recurved point.

Larva (fig. 45).—Antenna longer

than head with three setae of equal

length at apex, antennal tuft with

few hairs near middle. Upper

head hairs two to five; lower two

PN-860 to three. Comb on eighth segment

FiGUEE 43.—Aedes decticus larva.

Culex territans, and several species

of Aedes. At Fairbanks fourthstage larvae were taken on May

29. Adults believed to be decticus

were collected at Fort Yukon on

July 5.

Aedes diantaeus Howard, Dyar,

and Knab

Aedes diantaeus Howard, Dyar, and

Knab, Mosquitoes of No. and Cent.

Amer., v. 4, p. 758. 1917.

Female.—Torus with integument

of outer side yellow to light brown.

Occiput with pale-yellow scales.

Mesonotum with narrow median

brown stripes separated by faint

line of yellow scales ; posterior half

lines indistinct; sides pale yellowish. Postcoxal scale patch absent.

Stemopleuron with 12 to 20 setae,

of which a patch of 7 to 12 is just

PN-8B1

FiQTTBE 44.—Aedes diantaeus male

genitalia.
THE MOSQUITOES OF ALASKA 55

FIGURE 45.—Aedes diantaeus larva.

with about 6 to 13 scales, each scale

a long median spine without lateral

fringe of spinules. Air tube about

1 X 3; pectén extending to about

middle with one to three detached

teeth followed by tuft of long hairs.

Anal segment longer than wide,

nearly ringed by plate.

Bionomics.—This is a forest species, of which small numbers of larvae have been collected near Anchorage, Big Timber, Chitina, and

Fairbanks (map 4). Larvae tend

to be associated with Aedes functor

in semipermanent pools or along

the shallow marshy margins of permanent pools and ponds. Fourthstage larvae have been taken at

Fairbanks from May 26 until

June 10 and at Anchorage from

May 10 until October 8.

Aedes excrucians (Walker)

Culex excrucians Walker, Insecta Saundersiana. Díptera, v. I, p. 429. 1856.

Aedes alopo-notimi Dyar, Insecutor Inscitiae Menstruus 5: 98. 1917.

Female.—Torus with inner surface predominantly white scaled.

Mesonotum yellowish white with

median brown stripe, varied pattern of brown and white scales or

completely reddish-brown scaled.

Mesepimeral bristles absent or

rarely there may be one. Abdomen

black with basal segmental white

bands and frequently with scattered white scales. Wings predominantly dark scaled with pale scales

intermixed. Legs black with tarsal white bands broad on hind legs

and usually absent on last segment

of midtarsus and last two segments

of fore tarsus; tarsal claw large

with tooth long and parallel (fiff.

46,5).

Afole genitaJia (fig. 46, A).—

Sidepieces about three times as

long as wide ; apical lobe prominent

with small setae; basal lobe slightly

raised, rugose, and extending to

base of apical lobe, surface covered

with short setae. Claspette hirsute

except at apex; filament angularly

expanded to sharp point near base.

Larva ( fig. 47).—A n t e n n a e

shorter than head. Upper head

hairs triple, lower usually double.

Lateral abdominal hairs usually

double on first and second or third

segment and single on rest. Comb

on eighth segment of about 20 to 25

scales in triangular patch. Air tube

slender, about 4X1; pectén not

reaching middle with last two or

three teeth detached, tuft even with

last pectén tooth ; lateral valve with

hook-shaped setae at apex. Anal

segment longer than Avide, plate

extending well down side; anal gills

slightly longer than segment.
56 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

merous and troublesome. The

habit of biting during warm sunny

afternoons when few other mosquitoes are active increases the pest

importance of this species. Populations are more localized than those

of the dark-legged species, at least

during years when mosquitoes are

exceptionally numerous. They are

PN-8B3

riGUKE 46.—Aedes excrucians : A, Male

genitalia; B, claw of female.

Bionomics.—This species is

widely distributed through low forested areas from Wrangell north to

Fort Yukon and west to Naknek.

In the northwest it has been collected at Kotzebue and Noatak

(map 5). Larvae are prevalent in

semipermanent pools containing an

emergent cover of Carex rostrata

and Equisetum ßuviatile or in tidal

flats containing Triglochin. A water depth of 8 to 12 inches is favored. Peak adult emergence occurs at Anchorage near the first of

June and about 2 weeks later at

Fairbanks. The species is thus near

the end of the Aedes species succession series. Of the five band-legged

species, it appears to be the most nuPN-8B4

FiGUKE 47.—Aedes excrucians larva.

most numerous near rivers in areas

where there are extensive marshlands.

Aedes fitchii (Felt and Young)

Culex fitchii

(n.s.) 20

Felt

: 312.

and Young,

1904.

Science

Female.—Torus with white scales

on dorsal half. Mesonotum yellowish white to light brown with broad

median brown stripe or variable

pattern of brown and light scales.

Lower mesepimeral bristles none to
THE MOSQUITOES OF ALASKA 57

two, rarely three or four. Abdomen black with basal white bands,

sometimes with apical white scales

that may extend into median white

line. Wings dark scaled, usually

with admixture of white scales

along costa. Legs black ; tarsi with

basal white bands on all except last

two segments of fore tarsus and

first segment of midtareus, white

bands broader on hind legs; tarsal

claw with short tooth not parallel

with claw (fig. 48, B).

Male genitalia (fig. 48, A).—

Sidepieces about three times as long

as wide ; apical lobe prominent and

slightly elongated, surface clothed

with long setae bordered by number

of short ones ; basal lobe triangular,

densely tubercular with many setae,

those at margin of base longer and

preceded by spine. Claspette

lightly hii-sute except at apex ; filament short and sickle shaped with

notch at base.

Larva (fig. 49).—Upper head

hairs two to four, lower two to

three. Lateral abdominal hairs

FIGURE 48.—Aedes fitchii: A, Male genitalia ; B, claw of female.

FIGURE 49.—Aedes fitohii larva.

usually double. Comb on eighth

segment with many scales in triangular patch. Air tube slender

and tapering, four or more times

longer than wide ; closely set pectén

teeth to middle of tube, occasionally

with one or more teeth slightly detached, tuft of three to five long

hairs set close to end of pectén;

apical setae as long as lateral valve.

Anal segment longer than wide,

plate extending well down sides at

base; anal gills long and pointed.

Bionomics.—This species has

been collected at scattered localities

from Cook Inlet north to Fort

Yukon, west to Naknek, and in the

northwest at Kotzebue and Kivalina, but it appears to be most

numerous south of the Alaska
58 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

Range (map 8). Larvae occur in

semipermanent pools overgrown

witli Carex rostrata or Equhetum

-ßuwiatile and are usually found in

association with larvae of Aeden

excrucians. Fourth instars have

been collected at Fairbanks from

May 19 to June 15 and at Anchorage between May 17 and June 3.

N^owhere does the species appear to

be as common as exG?mcian-s.

Aedes flavescens (Müller)

Cnlex flavescens Müller, Fauna Insect.

Fridrichsdalina, p. 87. 1764.

Fevuile.—Torus with dark and

light scales. Mesonotum with golden-brown scales. Lower mesepimeral bristles usually absent. Abdomen completely covered with

dull-yellow scales or interspersed

with irregular areas of dark scales.

Wing with mixture of black and

pale-yellowish scales, pale scales

FIGURE 51.-

PN-858

-Aeáes flavescens larva.

FIGURE 50.—Aedes flavescens: A,

genitalia ; B, claw of female.

Male

predominating from base of costa to

humeral cross vein. Legs brown

with mixture of yellow scales;

tarsi with broad basal white bands ;

tarsal claw elongate with short

blunt tooth (fig. 50, 5).

Male genitalia, (fig. 50, A).—

Sidepieces more than two times as

long as wide; apical lobe prominently rounded with many setae;

basal lobe a rugose slightly elevated

area with many setae, stout spine,

and several long setae near base, lobe

extending nearly to base of apical

lobe. Claspette' lightly hirsute

witli three stout setae on inner margin of base ; filament angularly expanded to rounded point near base.

Larva (fig. 51).—Upper head

hairs usually three to four, lower

usually double. Comb on eighth

segment with about 20 to 28 scales,

each scale with long central spine

and small basal spinules. Air tube
THE MOSQUITOES OF ALASKA 59

tapering, about 3 X1 ; pectén reaching nearly to middle with or without one or two detached teeth.

Anal segment slightly longer than

wide; anal gills about as long as

segment.

Bionomics.—In Alaska this species is known only from the Cook

Inlet area, where it may be locally

abundant on or near tidal flats

(map 7). Lai'A'ae occur in shallow

pools containing emergent Triglochin and Scirpus. The pools originate from melting snow and ice

but may be maintained by seepage

and may be covered by the highest

summer tides. In 19-Í8 fourthstage lar\'ae were most numerous

about June 8. Adults were prevalent from June 14 through July 31

and persisted in reduced numbers

through August 18.

Aedes hexodontus Dyar

Aedes hexodontus Dyar, Insecutor Inscitiae Menstruus 4: 83. 1916.

Female.—Mesonotum yellowish

to light golden brown with paired

dark-brown lines and posterior half

lines. Postpronotum with setae in

single or irregular double row along

posterior margin. Postcoxal scales

present. Stemopleuron with scales

extending to frontal border. Scutellum with yellow or bronzy bristles. Probasisternum with white

scales on posterior part. Lower

mesepimeral bristles two or three.

Abdomen black with basal segmental white bands. Wings dark

scaled with patch of two or tliree

to many pale scales at base of costa.

Legs black with femora partially

pale scaled.

Aedes hexodontus as described

above has not been foimd in Alaska

but has been taken as far north as

Prince Rupert., British Cohmibia.

Knight [80) stated that hexodontus

"appears to have at least two general varieties that are based on both

adult (female) and lançai characters," but concludes that more larval associated females will be

needed to establish the validity of

these two forms.

In the "timdra" variety taken at

Umiat the mesonotum is brown and

the "darker markings are absent or

poorly demarcated." The wings

usually have a patch of white scales

on the costa. Other characters are

the same as described above.

Male genitalia (fig. 64, p. 67).—

Sidepieces three times as long as

broad ; apical lobe long and rounded with short, curved setae; basal

lobe flatly conical with numerous

setae and long cur^àng spine near

base. Claspette pilose, slightly

curved, and expanded near middle ;

filament shorter than stem, slightly

expanded at middle, and terminating in curved point. The characters of the male genitalia of this

species are the same as those of

A. punctor.

Larva (fig. 52).—Upper and

lower head hairs single to triple.

Lateral abdominal hairs single to

triple on first to sixth segment or

rarely four to six branched on

PN-8B»

FiGUEB 52.—Aede» hexodontus larva.
60 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

second segment. Comb on eighth

segment with 5 to 9 or rarely 10

scales in row. Air tube 3X1;

pect«n not quite reaching middle of

tube. Anal segment ringed by

plate or very narrowly open ventrally.

Bionomics.—This is typically a

tundra species, which is common

in northern and northwestern Alaska and south along the Bering Sea

to Naknek (map 7). It is also present in the Alaska Range and

Chugach Mountains above or at

least near the tree line. Larvae

prefer semipermanent pools in

Carex or Calamagrostis marshes

and are often taken in association

with larvae of Aedes puUatus, communis, and occasionally impiger or

punctor. Larvae of hexodontus

resemble punctor very closely, but

whenever the two were collected

together, hexodontus was always

more nearly mature. At Umiat,

hexodontus larvae were always

found in pure culture (Knight 81).

The adults are strong fliers and

remain active at wind speeds up

to 10 miles an hour. This species

is responsible for much of the severe

mosquito annoyance prevalent in

the tundra-covered areas of Alaska.

Aedes impiger (Walker)

Gulex impiger Walker, List of Dipterous Insects in Brit. Mus., pt. I, p. 6.

1848.

Aedes nearcticus Dyar, Canad. Arctic

Exped. Rpt 3(C), p. 32. 1919.

Aedes impiger, Vockeroth, Canad. Ent.

86: 109. 1954.

Not impiger of authors.

Female.—Mesonotum black and

sparsely covered with bronzy-brown

scales with or without mixture of

yellowish-white scales around sides,

entire surface with many black

bristles. Postpronotum with scales

scattered over posterior half. Postcoxal scale patch present. Lower

mesepimeral bristles three to eight.

Abdomen black with basal segmentai white bands. Wing scales

dark with pale scales extending

FIGURE 53.—Aedes impiger: A, Male

genitalia ; B, claw of female.

from base of costa to humeral

cross vein. Legs black with femora

and tibiae partially pale scaled;

tarsal claw sharply bent with slender tooth (fig. 53,5).

Male genitalia (fig. 53, A).—

Sidepieces about 31/2 times as long

as wide; apical lobe rounded, surface with few small setae; basal

lobe conically sloped to basal edge

with long setae and spine at margin,

rest of surface bare or with few

small setae. Claspette hirsute on

basal half; filament angularly expanded to its maximum width near

base.

Males of impiger and Aedes nig)ipes may be separated by the

shape of the hind tarsal claw, which

is the same in the males as in the

females.

Larva (fig. 54).—Both pairs of

head hairs single. Lateral abdominal hairs multiple on first segment

and double on second to fifth. Comb
THE MOSQUITOES OF ALASKA 61

PN-861

FiGUEE 54.—Aedes impiger larva.

on eighth segment of 8 to 16 scales,

each scale with long central spine

and series of smaller basal lateral

spines. Air tube about 2i/^ X 1;

pectén equally spaced on basal third

and followed by multiple tuft.

Anal segment as long as wide ; anal

gills stout and several times length

of segment.

Bionomics.—This is typically a

tundra species common in northwestern and northern Alaska (map

8). Larvae have been collected at

localities in the Alaska Range and

Chugach Mountains well below the

tree line, but it is doubtful that the

species is abundant except at higher

elevations. At Umiat larvae have

been taken from pools in SphagiiMm-heath bogs. Farther south

collections have been made from

temporary pools in Carex marshes.

Where impiger occurs, it is the first

species to emerge. In 1947 emergence at Umiat started about June

22 and continued until July 7

(Jachowski and Schultz 75).

Aedes implicatus Vockeroth

Aedes implicatus Vockeroth, Canad Ent

86: 110. 1954.

Aedes impiger of authors, not Walker.

Female.—Mesonotum with median oblong area of brown scales,

usually in form of broad stripe or

paired stripes; margins grayish

white. Postpronotum with setae

in single or irregular double row

along posterior margin. Postcoxal

scales present. Stemopleuron with

scales not extending to frontal

border (fig. 30, A, p. 44). Probasisternum without white scales on

posterior part. Lower mesepimeral

bristles one to three, or rarely with

none. Hypostigial spot with or

without white scales. Abdomen

with basal white bands. Wing

scales dark with patch of two or

three to many pale scales at base

of costa. Legs black with femora

pale beneath.

Male genitalia (fig. 55).—Sidepieces about four times as long as

wide. Filament of claspette angularly expanded to sharp point at

base. Other characters as in Aedes

cataphyUa, page 49.

Larva (fig. 56).—Antennae short

and spined. Upper and lower head

hairs single. Lateral abdominal

hairs double on first to fourth segment and single on fifth and sixth.

Comb on eighth segment with 15

to 25 scales, each scale with median

spine and lateral basal fringe of

slightly smaller ones. Air tube

about 21^ X 1 ; closely set pectén

teeth not reaching middle and followed by tuft. o,f three or four hairs.

Anal segment longer than wide,

plat« extending well down sides

and covered with minute spines;

anal gills one to two times as long

as segment.
62 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

FIGURE .55.- -Aedes implicatus

genitalia.

male

PN-863

FIGURE 56.—Aeáes implicatus larva.

Bionomics.—This species is common in central Alaska (map 3).

It has been recorded from as far

south as Juneau and from Kotzebue

in the northwest. It breeds in a

variety of temporary pools, and it

appears to be the first species in

the succession series. Adult emergence reaches a peak at Fairbanks

near the end of May and 2 to 3

weeks earlier at Anchorage. During 1948 it was thought to be tlie

fourth most numerous species at

Fairbanks, where it was observed

to be active and biting when the

sun was bright and the temperature

above 80° F. At such times it was

frequently the only dark-legged

Aedes in flight.

Aedes intrudens Dyar

Aedes intrudens Dyar, Insecutor Inscitiae Menstruus 7: 23. 1919.

Female.—Flagellum without

white scales on ventral side of first

segment. Mesonotum bronzy

brown with gray scales around margins and rarely with indications of

median brown stripes. Postcoxal

scale patch absent. Stemopleuron

with scales not extending to frontal

border. Posterior part of probasisternum bare. Lower mesepimeral

bristles none to four. Hypostigial

spot of scales present or absent.

Abdomen black with broad basal

white bands. Wing scales dark

with or without small patch of pale

scales at base of costa. Legs with

mixture of pale and dark scales;

tarsi mostly black.

Male genitalia (fig. 57).—Sidepieces about three times as long as

wide; apical lobe prominently

rounded with numerous rather long

setae; basal lobe represented by

large spine at base of one side and

two spines on raised projection on

other. Claspette with basal half

hirsute and forming sharp projection ending in stout setae at middle,

apical half slender; filament angu-
THE MOSQUITOES OF ALASKA 63

FiGUBE 57.—Aedes intrudens male

genitalia.

larly expanded to sharp point at

middle.

Larva (fig. 58).—Antennae shorter than head. Upper head hairs

usually four, lower two or three.

Lateral abdominal hairs double on

first segment and single on second

to sixth. Comb on eighth segment

of 10 to 16 scales, each scale with

long median spine. Air tube 21/2

XI; pectén reaching middle with

two or three detached teeth followed by tuft of five to seven hairs;

apical setae barely discernible.

Anal segment longer than wide,

plate extending to near ventral line

and ventral margin deeply incised ;

anal gills short and blimtly pointed.

Bionomics.—This is believed to

be an important pest species in the

Tanana watershed of central Alaska (map 5). Only a few larvae

have been found near Anchorage.

Temporary snowmelt pools in the

more open areas of black spnice

muskeg are. preferred lart^al habitats. Such pools are usually overgrown with C'arex or Calamagrostis

and are the most shallow and of

551810 0—61 5

shortest duration of the pools in

which mosquito larvae can be

found. At Fairbanks in 1948 peak

abundance of fourth-stage larvae

was reached about May 26, and the

pools were dry in advance of peak

emergence for either Aedes communis or functor. Larval population density seldom exceeded two

per selected dip, but the vast number of pools in which larva could

develop suggested that the adult

population ot intrudens might exceed that of communis or punctor.,

which originated from more congested larval populations restricted

to the relatively small number of

pools that persisted after June 5.

Adult collections made in 1948 and

subsequent years when the pools

that produce intrudens were dry

before the end of May confirmed

the relatively greater abundance of

intrudens in 1948.

PN-866

FiGUBE 58.—Aedes intrudens larva.
64 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

Aedes nigripes (Zetterstedt)

Ciilex nigripes Zetterstedt, Insecta Lapponica, p. 807. 1838.

Aedes nlpinus of authors (not Linnaeus).

Female.—Mesonotum black,

sparsely covered with bronzy-brown

scales or rarely with indications of

median dark lines, sides with or

without yellowish-white scales, entire surface covered witli many

black bristles. Postcoxal scale

patch present. Lower mesepimeral

bristles one to five. Abdomen

black with basal segmental white

bands. Wing scales dark with

pale scales extending from base of

costa to humeral cross vein. Legs

black with femora and tibia partially pale scaled; fore tarsal claw

with tooth about one-fourth as longas claw and not parallel (fig. 59, B).

PN-867

FIGURE 60.—Aedes nigripes larva.

JIale genitalia (fig. 59, A).—

Sidepieces over three times as long

as wide ; apical lobe small with few

short fine setae ; basal lobe conically

sloped to basal edge with large

spinelike setae on outer margin and

smaller ones on inner part. Claspette hirsute except on curved

apex; filament about same length

as stem, roundly expanded and ending in curved point.

Larva (fig. 60).—upper and

lower liead hairs single. Lateral abdominal hairs multiple on first and

second segments and double on

third to seventh. Comb on eighth

segment with 15 to 18 scales. Air

tube about 21/2 X 1 ; pectén I'eaching

beyond middle, last three teeth detached, hair tuft basad of last pectén

tooth. Anal segment ringed by

plate ; anal gills longer than

segment.

FIGURE 59.—Aedes nigripes : A, Male

genitalia; B, claw of female.

Bionomics.—This is a typical

tundra species, common along the

coast from Teller north to Point
THE MOSQUITOES OF ALASKA 65

Barrow and on the arctic side of

the Brooks Range (map 9). It is

the only species so far known from

Point Barrow. Larvae liave been

collected near Summit Lake in the

Alaska Range and at Thompson's

Pass in the Chugach Mountains.

From these records it appears likely

that nigripes occurs rather generally in mountain localities above

the tree line. It is one of the three

or four species that contribute to

the mosquito problem in northern

Alaska.

Aedes pionips Dyar

Aedes pionips Dyar, Insecutor Inscitiae

Menstruus 7 : 19. 1919.

Female.—Mesonotum with dullyellow or white scales, two broad

well-defined dark-brown stripes and

posterior half lines, median stripes

separated by line of pale scales.

Postpronotum with setae in single

or irregular double row along posterior margin. Postcoxal scales

present. Scutellmn with both dark

and light-colored bristles. Probasistemum with white scales on

posterior part. Lower mesepimeral bristles one to four, or rarely

with none. Abdomen with or without narrow basal white bands.

Wing scales dark with small patch

of pale scales at base of costa.

Ijegs black with femora partially

pale scaled.

Male genitalia.—The sidepieces

are slightly longer than those of

Aedes communis (fig. 40, p. 52).

There are no other taxonomic differences in the genitalia of these

two species.

The presence of the postcoxal

scale patch in pionips males may

be used to separate them from tlie

communis males in which the patch

is absent.

Larva (fig. 61).—Antennae long

and well spined. Upper head hairs

usually five, lower four. Comb on

eighth segment with 60 to 70 scales,

each scale with even fringe of

spinules. Air tube about 2^4X1;

PN-Í68

FIGURE 61.—Aedes pionips larva.

pectén evenly spaced, not reaching

middle and followed by large multiple tuft. Anal segment about as

long as wide, with plate reaching

only about half distance down

sides and with notched lateral

edges, spines on apex of anal plate

short and slender ; anal gills longer

than segment.

Bionomics.—This species is widely distributed throughout the

forested lowlands from Cook Inlet

north to the Yukon River (map 6).

In the northwest it has been collected beyond the tree line at Kivalina. Larvae have been fomid often

in temporary or semipennanent

pools in Sphagnum-\\QíiÚ\ bogs,

roadside ditches, tractor tracks, and

other small shallow bodies of water

in recently disturbed ground.

The species is rather common near

Anchorage but rare north of the

Alaska Range. Fourth-stage larvae

have been collected at Fairbanks be-
66 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

tween May 28 and June 13 and at

Anchorage from May 15 to July 27.

Peak adult emergence occurs from

8 to 10 days lat«r than that of

communis.

Aedes pullatus (Coquillett)

Gulex pullatus Coquillett, Wash. Ent

Soc. Proc. 6: 1Ö8. 1904.

Female.—Mesonotmn with paleyellowish to yellowish-brown scales,

two median stripes being sometimes

indistinct or absent. Postpronotum with setae in single or irregular

double row. Postcoxal scale patch

absent. Stemopleuron wàth scales

not extending to frontal border.

Probasistemum bare. Lower mesepimeral bristles one to five. Hypostigial spot of many white scales.

Abdomen black with basal white

bands. Wings dark scaled with

line of pale scales extending from

base of costa to humeral cross vein.

Legs black with femora and tibiae

partially pale scaled.

Male genitalia ^fig. 62).—Sidepieces about 31/^ times as long as

wide; apical lobe prominent and

PN-869

FIGURE 62.—Aedes pullatus male

genitalia.

PN-870

FiGXJEE 63.—Aedes pullatus lar-va.

somewhat elongated, ventral surface covered with numerous setae;

basal lobe represented by large

spine at margin and two adjacent

smaller spines. Claspette with basal half large, hirsute, and forming rounded projection at middle,

apical half slender; filament angularly expanded to rounded point

near middle.

Larva, (fig. 63).—Upper head

hairs three to six, lower two to four,

hairs short and tufts set close together. Lateral abdominal hairs

long and double or triple on first to

fifth segment and shigle on sixth.

Comb on eighth segment with many

scales in triangular patch. Air

tube 3 X 1 ; pectén teeth closely set,

not reaching middle, closely fol-
THE MOSQUITOES OF ALASKA. 67

owed by large 6- to 7-haired tuft;

apical setae shorter than lateral

valve. Anal segment longer than

wide, not ringed by plate, spines on

apex of anal plate long and slender ;

anal gills usually two or three times

longer than anal segment.

Bionomics.—This species is

found throughout Alaska in areas

near the tree line; however, larvae

have been collected at Wrangell and

Valdez at near sea level (map 4).

Small clear snowmelt pools in

Carex meadows produce larvae in

greatest numbers. The degree of

development shown by associated

lan^ae, and Frohne's obsei-vation

(38) that larvae were abundant in

pools in McKinley Park when

swarms of naale Aedes commimis

and impiger were already present,

indicate that jyidJatus emerges

somewhat later than hexodontus.,

punctor\ ivifiger^ and comviunis.

Records suggest that pullatus is

one of the most important pest species in the Chiigach Mountains and

Alaska Range at elevations above

2,000 feet.

Aedes punctor (Kirby)

Culex punctor Kirby, Fauna BorealiAmer., pt. 4, p. 309. 1837.

Aedes cycloceroulus Dyar, Insecutor

Inscitiae Menstruos 8: 23. 1920.

Aedes leuconotips Dyar, ibid 8: 24.

1920.

Aedes punctodes Dyar, ibid 10: 2. 1922.

Female.—Toms light brown to

black. Mesonotum pale yellow to

yellowish brown with paired darkbrown stripes and posterior submedian half stripes present or absent.

Postpronotum with setae in single

or irregular double row along posterior margin. Postcoxal scales

present. Stemopleuron with scales

extending to frontal border. Probasisternum with few or no scales.

Abdomen black with basal segmentai white bands. Wings completely dark scaled or with few

pale scales at base of costa. Legs

black, femora and tibia with or

without scattered pale scales.

The taxonomic status of punctor

is confused by the existence of a

remarkable variation of stiiicture

in the lai-vae and of color and scale

pattern in the adults. Larvae of

the foim prevalent along tlie southern coast are smaller, the aiial plate

does not form a complete ring, and

the anal gills are short. This form

has been treated by Knight {81)

and Frohne {31) as a distinct

species, punctodes Dyar. However, there is so much intergradation of the distinguishing characters that we have chosen to treat

punctodes as a synonym of punctor.

Among the adults there is also an

apparent difference, which distinguishes the tundra populations

from those of the forested areas.

The "tundra" variety has the torus

all dark and the mesonotum brown

scaled, with darker markings absent

or nearly so. The form from the

forested area as described above has

the torus paler laterally and the

yellowish mesonotum marked with

paired brown stripes.

Male genitalia (fig. 64).—The

characters of the male genitalia of

PN-sn

FIGURE 64.- -Aedes punctor male genitalia.
68 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

this species are the same as those

of Aedes hexodontu.s, pfig^ 59.

Larva (fig. 6.5).—Antennae short

and spined. Upper and lower head

hairs single or double. Lateral abdominal hairs usually single or

double on first to sixtli segments.

Comb on eighth segment with 10

to 19 stout scales in irregular row.

Air tube 2i/^ X 1; pectén fine and

not reaching middle of tube, tuft

centrally placed. Anal segment

ringed by plat© or narrowly open

ventrally; anal gills II/2 to 3 times

as long as anal plate.

Bionomics.—The typical variety

of functor is common throughout

the forested areas of central Alaska,

and the "tundra" variety has been

taken at Umiat, Kotzebue, and

Naknek (map 2). The pwictodes

form is abundant in the coastal area

from Cook Inlet southeastward at

least as far as Juneau. Over most

FIGURE 65.—Aedes punctor larva.

of central Alaska punctor is one of

the species most frequently encountered in larval collections. Shallow semipermanent pools in Sphagnwm-heath bogs and Carex or

Calamagrostis marshes are favored

larval habitats. Population densities are often as high as 300 per

dip. In southern and central Alaska larvae were usually found

associated with those of Aedes

communis and pionips. At Umiat,

Knight {81) found larvae of the

"tundra" variety in Sphagnumheath pools, which otherwise contained only Aedes nearcticus.

Frohne [36) reported that larvae

of the "tundra" variety of punctor

were more numerous than those of

any of the other species found at

Naknek during May and June of

1954 and that hatching started on

April 23. In 1948 fourth-stage

larvae of the typical variety were

collected from May 10 through

September 15, with peak abundance

during the first half of June. At

Fairbanks fourth-stage larvae were

found from May 24 through July 19,

with peak abundance about June 5.

At Umiat, Knight {81) observed

peak abundance near the end of

June.

Aedes riparias Dyar and Knab

Aedes riparius Dyar and Knab, N.Y.

Bnt. Soc. Jour. 15 : 213. 1907.

Female.—Torus with inner surface predominantly dark scaled.

Mesonotum with golden-brown

scales and few yellowish-white

scales around margins. Mesepimeral bristles absent. Abdomen

usually with evenly intermingled

dark and white scales with or without partial basal white bands;

venter white scaled or with irregular dark-scaled medium areas.

Wings predominantly dark scaled

wáth pale scales intermixed. Femora, tibiae, and first tarsal segments

largely pale scaled, tarsi with basal

white bands, which are broader on
THE MOSQUITOES OF ALASKA 69

hind legs; tarsal claw with short

tooth not parallel with claw (fig.

66, B ).

Male genitalia (fig. 66, A).—

Sidepieces about three times as long

as wide ; apical lobe prominent and

rounded with many curved setae;

basal lobe projected in long cone

shape at right angles to sidepiece,

surface with many setae apically

and stout spine at margin with long

setae adjacent to it. Claspette

lightly hirsute; filament angularly

expanded to its maximum width

near base.

Larva (fig. 67).—Antennae shorter than head. Both pairs of head

hairs usually double. Comb on

eighth segment with seven or eight

thomlike scales in irregular row.

Air tube about 3 X1 ; pectén reaching nearly to middle with last two

teeth detached and followed by

three-haired tuft; apical setae

barely discernible. Anal segment

with plate nearly reaching ventral

line near base ; anal gills short and

pointed.

PN-873

FioxTBE 66.—Aedes riparius: A, Male

genitalia ; B, female claw.

PN-8T4

FiQUKE 67.—Aedes riparius larva.

Bionomics.—Records for this

species are based on adults collected

at several localities in the Yukon

basin of central Alaska (map 7).

It appears to be a rare species

found in the vicinity of black

spruce muskeg. Its large size and

golden color make it conspicuous

among the innumerable smaller

dark Aedes.

Aedes Stimulans (Walker)

Culex Stimulans Walker, List of Dipterous Insects in Brit. Mus., pt. I,

p. 4. 1848.

Female.—Torus with or without

white scales on dorsal half. Mesonotum yellowish wliite to light

brown with broad median brown

stripe of variable pattern of brown

and light scales. Lower mesepimeral bristles three or four,
70 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

FIGURE 68.- -Aedes Stimulans

genitalia.

PN-876

male

rarely one or two. Abdomen black

with basal segmental white bands.

Wings completely dark scaled or

with admixture of white ones along

costa. Legs black, tarsi with basal

white bands on all except last two

segments of fore tarsus and first

segment of midtarsus, white bands

broader on hind legs; tarsal claw

with short tooth not parallel to

claw.

Male genitalia (fig. 68).—Sidepieces about three times as long as

wide; apical lobe with rather long

setae; basal lobe low rounded with

many short, setae and stout marginal spine. Claspett« hirsute except at apex ; filament thin and angularly expanded to sharp point at

middle.

Larva (fig. 69).—Upper head

hairs three or four, lower two or

three. Mesothoracic hair No. 1

double or triple. Comb on eighth

segment with about 22 to 35 scales,

each scale with median spine and

series of smaller lateral ones. Air

tube about 3 X 1 ; pectén teeth extending nearly to middle; apical

setae shorter than lateral valve.

Anal segment longer than wide with

plate extending well down sides;

anal gills about as long as segment.

Aedes Stimulans larvae taken in

Alaska have three or four upper

and two lower head hairs instead of

two upper and one lower as in Stimulans larvae taken farther south.

Dyar described larvae having the

larger number of head hairs as

Aedes Tnercurator^ but this species

has since been considered a synonym

of stinmlans by Dyar and other

authors.

Bionomics.—This species is rather common near Fairbanks and has

been taken at several localities between the Chugach Mountains and

Alaska Range (map 6). Larvae are

found in semipermanent pools overgrown with Equisetum fluviatile or

Potentilla palustHs. Fourth-stage

larvae have been collected at FairPII-«7«

FiGUEE 69.—Aedes atvmulanê larva.
THE MOSQUITOES OF ALASKA 71

banks between June 3 and 12. The emergence is virtually complete bedevelopment period coincides with fore the two other band-legged

that of Aedes punctor, and data ob- species, Aedes excrucians and fitchii^

tained in 1948 indicate that adult reach peak emergence.

GENUS CULISETA FELT

KEYS TO SPECIES

Adults

1. Femora with distinct subapical white rings particeps, p. 75

Femora without subapical white rings 2

2. Sternopleuron with scales extending to frontal border; torus with white

scales 3

Sternopleuron with white scales not extending to frontal border; torus

without white scales 4

3. Tarsi with narrow white rings on some segments; cross veins without

scales incidens, p. 74

Tarsi with broad white rings; cross veins with scales alaskaensis, p. 72

4. Tarsi with pale-white rings at both ends of tarsal joints; wings without

spots morsitans, p. 76

Tarsi without white rings; wings with faint spots impatiens, p. 73

Larvae

1. Air tube with normal pectén teeth on basal fourth not followed by long

hairs morsilans, p. 76

Air tube with normal pectén teeth near base followed by series of long

hairs extending beyond middle 2

2. Upper and lower head hairs multiple and about equal in number and

length impatiens, p. 73

Upper head hairs short and multiple, lower longer and less numerous. _ 3

3. Postclypeal hairs four to five branched and about as large as head

hairs; posterior margin of anal plate with short spines at apex near

dorsal brush particeps, p. 75

Postclypeal hairs smaller and more delicate than head hairs; anal

plate without spines 4

4. Antennae pigmented and prominently spined; anal plate pierced by

two or three tufts__ alaskaensis, p. 72

Antennae not pigmented and not prominently spined; anal plate either

without or pierced by one or two tufts incidens, p. 74

Male Genitalia

1. Apical lobe absent morsilans, p. 76

Apical lobe present .-- 2

2. Eighth segment with row of 20 to 40 short spines on basal margin;

basal lobe large with single spinelike setae impahens, p. 73

Eighth segment with less than 12 spines on basal margin; basal lobe

with 2 or 3 spines . _^

3. Apical lobe with many setae and one spine mcidens, p. li

Apical lobe with setae only

4. Eighth segment without spines or with single short spine at center of

basal margin particeps, p. U

Eighth segment with about eight stout spines alaskaensis, p. 7^
72 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

Culiseta alaskaensis (Ludlow)

Theohaldia alaskaensis Ludlow, Ganad.

Ent. 38: 326. 1906.

Female ( frontispiece).—Torus

white scaled. Flagellum with first

segment white scaled ventrally.

Mesonotum with even mixture of

brown and white scales, sometimes

marked with pair of median white

spots. Sternopleuron with scales

extending to frontal border. Abdomen black with basal segmental

white bands. Wing scales dark,

scales forming spots at base and

fork of second vein, along cross

veins, at base and fork of fourth,

upper fork of fifth, and middle of

sixth veins. Legs black with wide

basal white bands that are broadest

on hind legs.

Male genitalia (fig. 70).—Sidepieces more than twice as long as

wide; apical lobe a low rounded

area densely covered with small

setae ; basal lobe large, conical, covered with small setae, apex with two

FIGURE 70.- -Culiseta alaskaensis

genitalia.

PN-e77

male

PN-878

FiGTJKE 71.—Culiseta alaskaensis larva.

stout spines. Lobes of ninth tergite

broad, rounded, and bearing 7 to 10.

slender setae. Eighth segment with

about eight stout spines.

Larva (fig. 71).—Antennae pigmented, distinctly spined, and equal

to or slightly shorter than distance

between two antennae. Upper

head hairs five or six, lower three

or four. Postclypeal hairs smaller

and more delicate than head hairs.

Air tube 2 X1 ; 8 to 12 pectén teeth

on basal fourth followed by long

hairs that extend nearly to apex,

paired tufts arising close to base

between pectén rows. Anal segment about as long as wide, ringed

by plate with two or three tufts

piercing plate.

Bionomics.—This species is common in forested lowland areas from

Haines north to the Yukon Eiver

and west to Naknek (map 12).
THE MOSQUITOES OF ALASKA 73

Larvae develop in shallow semipermanent or permanent pools that

are clogged with debris and vegetation, often in association with

Anopheles earlei, Culex terntans,

and in the more southern part of

its range with Culiseta iynpatiens.

Overwintering adults appear during early April near Anchorage

and in early May at Fairbanks.

Activity is greatest during May and

the first half of June. During 1948

fourth-stage larvae were found at

both Fairbanks and Anchorage

from the middle of June until midSeptember. Peak abundance at

both localities occurred about the

second week in July. Adults

emerge from late June until fall,

and studies by Frohne {33) have

shown that the females do not take

blood meals until the following

spring.

In some localities alashaensis is

sufficiently numerous to cause serious annoyance for a full month or

even 6 weeks in advance of Aeden

emergence. Its habit of emerging

from hibernation while much of

the winter snow still covers the

ground has caused it, together with

impatient, to be known locally as

"the snow mosquito."

Culiseta impatiens (Walker)

Culex impatiens Walker, List of Dipterous Insects in Brit. Mus., pt. I, p. 5.

1848.

Female.—Torus and first segment of flagellum without white

scales. Mesonotum with brown

and yellowish scales, two fine pale

lines extending posteriorly from

median pale patches and variable

pattern of other pale scales.

Stemopleuron with scales not extending to frontal border. Abdomen black with basal segmentai

white bands. Wing scales brown

and aggregated to form faint spots

at forks of second and fourth veins

and bases of second and third veins.

Legs black, femora white tipped.

Male genitalia (fig. 72).—Sidepieces stout conical, about twice as

long as wide; apical lobe a small

slightly elevated chitinized area

with long setae; basal lobe large

and conical in outline, apex rounded with one large spinelike seta

and several smaller ones. Lobes of

ninth tergite only slightly separated and each bearing about 10

long setae. Eighth sèment with

row of 20 to 40 short stout spines on

basal margin.

Larva (fig. 73).—Antennae slightly longer than distance between

two antennae. Both pairs of head

hail's multiple and long. Lateral

abdominal hairs multiple on first

to fifth segment and double on

sixth. Air tube stout, 2 X 1 ;

pectén of 10 to 15 teeth on basal

fourth followed by long hairs that

nearly reach apex of tube, paired

tufts large and arising close to base

between rows of pectén. Anal segment wider than long, ringed by

plate with two to three anterior

PN-879

FIGURE 72.—Culiseta impatiens male

genitalia.
74 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

PN-880

FIGURE 73.—CuUseta impatiens larva.

tufts of ventral brush puncturing plate and with tuft of small

hairs near posterior margin; anal

gills longer than segment.

Bionomics.—This species occurs

in the Panhandle northward to the

Cook Inlet area, where it seems to

be more nmnerous than Culiseta

aldskaen.ús. In the west it has been

reported from Naknek {36) and

Unalakleet, and one adult has been

taken at Nome (map 11). Although it occurs at Fairbanks, the

species appears to be quite uncommon north of the Coast Ranges.

Larvae are found in semipermanent

or permanent pools of the same

kind as those described for

alaskaensis. In fact, larvae of the

two species are usually taken from

the same pools, at least in the Cook

Inlet area. During 1948 the peak

abundance was not reached until

the second week in August or almost a montli later than that of

alaskaensw. Also during 1948 no

impatiens adults were seen prior to

May 1, but they were more numerous than nlaskaensis after May 19.

Few adults were seen after the

middle of June.

Culiseta incidens (Thomson)

Culex incidens Thomson, Kongl. Sven.

Freg. Resa, Dipt., v. 6, p. 443. 1868.

Female.—Torus white scaled.

Flagellum with first segment white

scaled ventraUy. Mesonotum with

dark-brown scales and mixture of

yellowish scales, some of which

form partial longitudinal lines or

spots. Stemopleuron with scales

extending to frontal border. Abdomen black with basal segmental

white bands. Wing scales dark,

aggregated into patches on fork

and base of second vein, fork of

second and fourth veins, upper fork

of fifth and middle of sixth veins.

Legs dark brown with narrow

faint-white rings on bases of some

of tarsal joints, femora and tibia

with narrow white rings at their

apices.

Male genitalia (fig. 74).—Sidepieces more than twice as long as

wide; apical lobe a small elevated

area with a number of small setae

and long spine; basal lobe small

and conical with small setae, apex

with two stout spines. Lobes of

ninth tergite slightly separated,

each bearmg five to eight rather

long setae. Eighth segment with

five to eight spines on basal margin.

Larva (fig. 75).—Antennae not

pigmented and not prominently

spined. Both pairs of head hairs
THE MOSQUITOES OF ALASKA 75

multiple, lower tufts longer and

fewer in number than uj^per.

Postclypeal hairs smaller and more

delicate than head liairs. I^ateral

abdominal hairs miütiple on fii-st

and second segments and double on

third to sixth. Air tube stout,

about 2X1; pectén witli few basal

teeth that have one or two minute

denticles, teeth followed by long

hairs to apical third of tube, multiple tuft near base between rows of

pectén. Anal segment ringed by

plate; tufts of ventral brash absent

or with one to two puncturing plate

and a small one- to three-haired tuft

on lateral posterior margin; anal

gills slightly longer than segment.

Bionomics.—Lan^ae of tliis species and one adult liave been collected at Juneau (FrohneJÖ) (map

12). Records ifrom Matanuska

(Stage and Chamberlin 99) are believed to have been in error and

probably refer to OuUseta

alaskaerisis.

FiGtniE 74.—Culiseta incidens

genitalia.

PN-88I

male

PN-882

FIGURE 75.—Culiseta incidenn larva.

Culiseta particeps (Adams)

Culex particeps Adams, Kans. Univ. S'i.

Bui. 2, p. 26. 190.3.

Culiseta maccraekcnae Dyar and Knab,

Wash. Biol. Soc. Pro-- 19: 13.3.

1906.

Female.—M e s o n o t u m dark

brown with light-brown median

stripe and narrow white posterior

half lines; sides, anterior margin,

and margins of antescutellar space

with mixture of white scales. Abdomen black with basal segmental

white bands and few scattered

wliite scales. Wing scales black

with few pale scales on costal veins,

dark scales forming spots at base

of second vein, forks of second and

fourth veins, upper fork of fifth

vein, and on cross veins. Legs

black with part of inner side wliite
76 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

scaled, femora with subapical white

ring followed by black ring, apical

segments of tarsi without rings and

succeeding tarsi with gradually

broadening white rings.

Male genitalia.—Sidepieces about

three times as long as wide; apical

lobe a small elevated area with

number of long setae; basal lobe

small and conical with many small

setae, apex with two or three stout

spines. Lobes of ninth tergite not

separated but indicated by two

large groups of small spines.

Eighth segment without spines or

with one spine at center of basal

margin.

Larva.—Both pairs of head hairs

multiple, lower with about three

long hairs, upper more numerous

and shorter. Postclypeal hairs

four to five branched and about as

long as head hairs. Mesothoracic

hair No. 3 less than six times prothoracic hair No. 0. Air tube stout,

about 2 X 1 ; pectén with few basal

teeth followed by long hairs that

extend nearly to apex of tube,

paired tuft near base of tube between rows of pectén. Anal segment ringed by plate with two

anterior tufts of ventral brush arising from cleft in plate and small

patch of short bristles near apex of

plate ; anal gills slightly longer than

segment.

Bionomics.—Larvae believed to

belong to this species were collected

from a roadside ditch at Wrangell

(Frohne and Sleeper 1^2) (map 12).

If they are correctly identified, this

is the only record for the species

north of southwestern Oregon.

Culiseta morsitans (Theobald)

Culex morsitans Theobald, Monog. of

Culicidae of World, v. II, p. 8. 1901.

Female.—Torus and first segment

of flagellum not white scaled.

Mesonotum brown with mixture of

yellowish scales around margins,

pair of faint nearly bare median

stripes, and posterior yellowishwhite half lines. Stemopleuron

with scales not extending to frontal

border. Abdomen brown scaled

with scattered yellowish-white

scales, mostly heavily concentrated

along apices and bases of segments,

or these may occasionally form

basal pale bands only. Wing scales

dark with pale scales at base of

costa. Legs dark with faint-white

rings at both ends of tarsal joints.

Male genitalia (fig. 76).—Sidepieces conical, more than twice as

long as wide; apical lobe absent;

basal lobe prominent and conical

with three to five spines on apex

and small setae on sides. Lobes of

ninth tergite with broad projections, each with 6 to 12 slender setae.

Eighth segment with group of small

spines centrally on basal margin.

Larva (fig. 77).—Upper head

hairs multiple, lower double. LatPIÍ-883

FIGURE 76.—Culiseta morsitans male

genitalia. (Courtesy A. R. Barr.)
THE MOSQUITOES OF ALASKA 77

PN-884

FiGUBE 77.—Culiseta morsitans larva.

eral abdominal hairs multiple on

first and second segments, single

and long on third to sixth. Air

tube about 6X1; pectén with six

to nine teeth on basal fourth, paired

tuft at base between rows of pectén.

Anal segment longer than wide and

ringed by plate; anal gills slender

and longer.than segment.

Bionomics.—This infrequently

collected species has been recorded

from scattered localities within the

forest zone from Anchorage noirth

to Fairbanks and in the southwest

at Naknek (map 10). Larvae are

often found associated with Aedes

excrv/dans in semipermanent and

permanent pools that are overgrown with Carex rostrata. In the

Anchorage area Frohne {32) found

larvae associated with Culiseta alaskaensis and impatiens in MyricaSphagnum bogs. In 1948 fourth

instars were found at Fairbanks

from June 15 to July 19 and at

Anchorage from May 31 to August 16. Little is known concerning the biology of this species. It

is not known to bite man.

GENUS ANOPHELES

MEIGEN

Anopheles earlei Vargas

Anopheles earlei Vargas, Pan Amer.

Union Bol. de la Ofic. Sanit. 22:8.

1943.

Female.—Palpi as long as proboscis, dark brown. Mesonotum

with pruinose gray stripe bordered

by dark bands, median stripe with

hairlike yellowish scales. Wing

scales dark brown and aggregated

into spots at base of second vein, at

forks of second and fourth veins,

and at cross veins, second vein between cross veins and fork with

niunerous dark scales, spot of pale

scales at apex of wing. Legs black,

apices of femora and tibiae with

pale-yellowish scales.

Male genitalia (fig. 78).—Claspettes bilobed, with two (sometimes

three) spines on ventral lobe and

usually with two spines on dorsal

lobe. Claspers with bases covered

with dense patch of nonpapillated

hairs. Mesosome with four pairs of

nonserrated leaflets. Ninth tergite

FIGURE 78.—Anopheles earlei male genitalia.
AGR. HANDBOOK 182, U.S. DEPT. OF AGRICtJLTURE

PN-886

FIGURE 79.—Anopheles carlei larva.
THE MOSQUITOES OF ALASKA 79

with lobes usually short and with

apex broadened or obliquely trmicate.

Larva (fig. 79).—Head longer

than wide. Postclypeal hairstwo to

five branched, brandling usually

short distance from base. Inner

clypeal hairs bifurcate near middle

or with few additional fine branches

and set close together. Frontoclypeal sclerite pale banded. Abdomen

with palmate tufts on third to

seventh segments, antepalmate haii-s

on fourth and fifth segments with

two to four branches. Anal segment longer than wide, dorsal plate

with long single latei-al hair; anal

gills as long as segment and bluntly

pointed.

Bionomics.—This rather uncommon species is widely distributed

throughout the forested lowlands

from Cook Inlet north to the Yukon

River (map 10). Larvae live in

pools and ponds or along lake shores

that are permanent or dry for only

a short time during the late summer. These habitats usually support an emergent cover of Equiseturn, Typha^ or Carex rostrata, and

larvae are always associated with

floating or partly submerged plants

such as Lemna, RanvMctdus, and

Utricidana. Overwintering adults

appear in early May and disappear

during early June. In 1948 fourth

instars were most numerous about

July 1 at Fairbanks and July 7 at

Anchorage. Few larvae were collected after July 10. Although the

adult females bite readily, they have

not been observed in numbere sufficient to cause serious annoyance.

Alaskan records for Anoph-ehs

mamdipennis and occidentalis refer

to earlei Frohne {37) has reported

that although Alaskan earlei appears structurally similar to earlei

of Montana, there are pronounced

physiological and behavioral differences between the two populations.

GENUS CULEX LINNAEUS

Culex territans Walker

Culcx tcrritnns-Wa.\kev, Insecta Saundersiana, Diptera, v. I, p. 428. 1856.

Ciih'x apicaliis Adams (of Dyar and other

authors, not Adams).

Female.—M e s o n o t u m brown

scaled witli median indistinct

nearly bare lines and usually with

two median spots of yellowish

scales. Abdomen black scaled with

apical segmental white bands.

Wing scales all black. Legs black,

undersurface partially white scaled.

J/ale genitalia (fig. 80).—Sidepieces more than twice as long as

wide; subapical lobe with two

large rods, spine, and five hooked

FIGURE 80.—Culex territans male genitalia.
80 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

filaments, fii-st three partially serrated. Tenth steniite prominent,

apex broad, extending beyond mesosome and terminating in row of

short setae. Mesosome halves with

relatively even oblong outlines terminating apically in rounded serrated margin, halves joined by

sclerotized band near apex.

Larva (fig. 81).—Antennae large,

cylindrical, and spined. Head hairs

single or double. Lateral abdominal hairs multiple on first and second segments and double on third

to sixth, secondary haii-s numerous

and well developed. Comb on

eighth segment with numerous

scales in triangular patch. Air tube

long and tapering, about 7X1;

pectén of 12 to 14 teeth on basal

third of tube with four pairs of

prominent tufts beyond pectén and

also sometimes small fifth pair near

apex. Anal segment ringed by

plate, longer than wide.

Bionomics.—This species is distributed throughout the forested

lowlands from Valdez and the Cook

Inlet area north to the Yukon River

(map 9). Larvae live in pennanent

or almost permanent pools and

ponds as well as along lake shores.

Favored habitats support an emergent cover of Eqimetum., Carex

rostrata., or Scirpus validm, contain

Ranimculus, and often have a floating cover of Lemna. In 1948

fourth-stage larvae were found at

Anchorage from June 16 through

August 20 and were most numerous

about July 27. At Fairbanks they

were taken from June 9 through

September 7, with a peak abundance

about July 3. Larvae are able to

survive in pools containing such

high populations of insect predators that all Aedes and Gvliseta

larvae are eliminated. Adults are

seldom seen. They are known to

feed on frogs.

PN-8g8

FIGURE 81.—Gulex territans larva.
THE MOSQUITOES OF ALASKA 81

Literature Cited

(1) ABEBCEOMBIE, W. R.

1900. A MILITARY REC0NN0I8SANCE OF THE COPPER KIVER VALLEY. 1% COMpilation of Narratives of Explorations in Alaska. 56th Cong., 1st

Sess., Senate Kpt. No. 1023. 856 pp., illus. Wash., D.C.

(2) ALTMAN, R. M., and SMITH, C. N.

1955. INVESTIGATIONS OF REPELLENTS FOR PROTECTION AGAINST MOSQUITOES

IN ALASKA, 1953. Jour. Econ. Ent. 48: 67-72.

(3) AMERICAN MOSQUITO CONTROL ASSOCIATION.

1948. THE USE OF AIRCRAFT IN THE CONTROL OF MOSQUITOES. AMCR. M06-

quito Control Assoc. Bui. 1, 46 pp., illus.

(4)

1952. GROUND EQUIPMENT AND INSECTIOIDB» FOE MOSQUITO CONTROL. Amer.

Mosquito Control Assoc. Bui. 2,116 pp., illus.

(5) APPLEWHITE, K. H., and CROSS, H. F.

1951. FURTHER STUDIES OF REPELLENTS IN ALASKA. JoUT. EcOn. Ent. 44 :

19-22.

(6) KEEGAN, H. L., and HEDEEN, R. A.

1953. RESIDUAL EFFECTIVENESS OF DDT SPRAYS AGAINST MOSQUITO BREEDING IN

ALASKA. (Scientific Notes) Jour. Econ. Ent. 46: 516-517.

(7) and SMITH, C. N.

1950. FIELD TESTS WITH MOSQUITO AND SAND FLY REPELLENTS IN ALASKA.

Jour. Econ. Ent. 43: 353-357.

(8) BACON, R. W.

1946. EFFECTIVENESS OF INSECT WIRE SCREENING. MOSQULTO NSWS 6 : 85-88,

illus.

(9) BARBER, M. A.

1928. THE FOOD OF CULICINE LARVAE. U.S. Treas. Dept. Pub. Health Rpts.

43: 11-17.

(9a) BABR, A. R., and EHELICH, P. R.

1958. MOSQUITO RECORDS FROM THE CHUKCHI SEA COAST OF NORTHWESTERN

ALASKA. Mosquito News 1.6 : ±,^±-±.

(10) BATES, M.

1949. THE NATURAL HISTORY OF MOSQUITOES. 379 pp., illus. N.T.

(11) BECKEL, W. E.

1954. THE IDENTIFICATION OF ADULT FEMALE AEDES MOSQUITOES (DíPTERA,

CULIOIDAE) OF THE BLACJK-LEGGED GROUP TAKEN IN THE FIELD AT

CHUECHUL, MANITOBA. Canad. Jour. Zool. 32: 324^330, illus.

(12)

1954. THE LACK OF AUT0LY8I8 OF THE FLIGHT MUSCLES OF AEDES COMMUNIS

(DEXJEER) (CULICüDAE) IN THE LABORATORY. Mosquito News 14:

124^127, illus.

(13) BiDLINGMAYER, W. L., and SCHOOF, H. F.

1956. OUTDOOR RESIDUAL TREATMENTS OF PREMISES FOE CONTROL OF SALTMARSH MOSQUITOES. Mosquito News 16:17-19.

(14) BLANTON, F. S., HUSMAN, C. N., TRAVIS, B. V., and WILSON, C. S.

1949. CONTROL OF ALASKAN MOSQUITO ADULTS BY AERIAL SPRAYS. JoUr.

Econ. Ent. 42 : 106-109.

(15) TRAVIS, B. V., SMITH, N., and HUSMAN, C. N.

1950. CONTROL OF ADULT MOSQUITOES IN ALASKA WITH AERIAL SPRAYS. JoUr.

Econ. Ent. 43 : 347-350.

(16) BROWN, A. W. A., and MULHERN, T. D.

1954. A REPORT ON TESTS OF THE PERFORMANCE OF ADULTICIDING MACHINES IN

CALIFORNIA. Mosquito News 14:175-186, illus.

(17) and WATSON, D. L.

1953. STUDIES ON FINE SPRAY AND AEROSOL MACHINES FOE CONTROL OF ADULT

MOSQUITOES. Mosquito News 13: 81-95, iUus.

(18) CARPENTER, S. J., and LACASSE, W. J.

1955. MOSQUITOES OF NORTH AMERICA (NORTH OF MEXICO). 360 pp., illUS.

Los Angeles.

(19) CHAMBERLIN, J. C, and LAWSON, F. R.

1945. A MECHANICAL TRAP FOR THE SAMPLING OF AERIAL INSECT POPULATIONS.

Mosquito News 5 : 4-7, illus.

(20) COQUILLETT, D. W. T^ir ^ A „H

1900. PAPERS FROM THE HARRIMAN ALASKA EXPEDITION IX. Wash. Acaa.

Sei. Proc. 2: 389-464.
82 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

(21) CBAIG, G. B., JR., and PIENKOWSKI, R. L.

1955. THE OCCURRENCE OF AEa)ES CANADEN8I8 (THEOBALD) IN ALASKA. Wash.

Ent. See. Proc. 57 : 268.

(22) CROWE, R. „ ,^

1948. THE PLUMBER'S NIGHTMARE "GROWS UP" AND NOW HAS A ' COLT. Mosquito News 8 : 110-111, illus.

(23) CULVER, D., CAPLAN, P., and THIELEN, W.

1956. CONSIDERATION OF HUMAN EXPOSURE TO MALATHION USED IN POPULATED

AREAS. Mosquito News 16: 81-83, illus.

(24) CURTIS, L.

1954. A PORTABLE PNEUMATIC SPRAT UNIT. Mosquito News 14: 58-61, illus.

(25) DEONIER, C. C, and GILBERT, I. H.

1950. RESISTANCE OF SALT-MARSH MOSQUITOES TO DDT AND OTHER INSECTICIDES. Mosquito News 10: 138-143.

(26) DICE, L. K

1943. THE BiOTic PROVINCES OF NORTH AMERICA. 78 Pp., illus. Ann Arbor,

Mich.

(27) DYAB, H. G.

1928. THE MOSQUITOES OF THE AMERICAS. 616 pp., illus. Wash., D.C.

(28) EDDY, G. W., HOPKINS, T. L., and ROBBINS, W. E.

1958. RESISTANCE OF CULEX TARSALIS OOQ. TO DDT IN OREGON. JOUr. EcOn.

Ent. 51: 56-58.

(29) FROHNE, W. C.

1951. SEASONAL INCIDENCE OF MOSQUITOES IN THE UPPER COOK INLET, ALASKA.

Mosquito News 11: 213-216.

(30)

1952. MOSQUITO NEWS FROM ALASKA. Mosquito News 12: 263.

(31)

1953. MOSQUITO BREEDING IN ALASKAN SA^T MARSHES, W^TH ESPECIAL REFERENCE TO AEDES puNCTODES DTAR. Mosquito News 13 : 96-103.

(32)

(33)

(34)

(35)

(36)

(37)

(38»

1953. NATURAL HISTORY OF OULISETA IMPATIENS (WLK.), (DÍPTERA, CULIciDAE), IN ALASKA. Amer. Micros. Soc. Trans. 72: 103-118.

1954. BIOLOGY OF AN ALASKAN MOSQUITO, CULISETA ALASKAENSIS (LUDL.).

Amer. Bnt. Soc. Ann. 47: 9-24, illus.

1954. MOSQUITO DISTRIBUTION IN ALASKA WITH ESPECIAL REFERENCE TO A NEW

TYPE OF LIFE CYCLE. Mosquito News 14 : 10-13.

19.55. CHARACTERISTIC SADDLE SPINES OF NORTHERN MOSQUITO LARVAE. Amer.

Micros. Soc. Trans. 74: 295-302.

1955. TUNDRA MOSQUITOES AT NAKNEK, ALASKA PENINSULA. AmCr. MicrOS.

Soc. Trans. 74 : 292-295.

1956. THE EGG AND IDENTITY OF ALASKAN ANOPHELES. MoSquitO NeWS 16:

308.

1957. RECONNAISSANCE OF MOUNTAIN MOSQUITOES IN THE MCKINLEY PARK

REGION, ALASKA. Mosquito News 17 : 17-22.

(39) and FKOHNE, R. G.

19.52. MATING SWARMS OF MALES OF THE ^tOSQUIT0, AEDES FUNCTOR (KIRBY),

IN ALASKA. Mosquito News 12 : 248-251.

(40) and í'ROHNE, R. G.

19.54. HREEDING PI ACES OF AEDES PSEUDODIANTAEUS SMITH AND DIANTAEUS

II., D., & K. IN ALASKA. Brooklyn Ent. Soc. Bui. 49: 9.5-99.

^41) and FROHNE, R. G.

1954. DIURNAL SWARMS OF CUI.EX TE21RITANS WALKER, AND THE CREPUSCULAR

SWARMING OF AEDES ABOUT A SMALL GLADE IN ALASKA. MOSqUitO

News 14: 62-64.

(42) and SLEEPER, D. A.

1951. RECONNAISSANCE OF MOSQUITOES, PUNKIES. AND BLACKFLIES IN SOUTHEAST ALASKA. Mosquito NevTS 11: 209-213.

(43) GAHAN, J B., BERTHOLF, J. H., DAVIS, A. N.. JR.. and SMITH, C. N.

?9o6. FIELD TESTS WITH TWO PHOSPHOROTHIOATES AGAINST RESISTANT BALTMARSH MOSQUITOES. Mosquito News 16: 91-93.
THE MOSQUITOES OF ALASKA. 83

(44) GAHAN, J. B., LABBECQXJE, G. C, and BOWEN, C. V.

1955. AN APPLICATOR FOR ADDING CHEMICALS TO FLOWING WATER AT UNIFORM

RATES. Mosquito News 15 : 143-147, illus.

(45) and MULHERN, T. D.

1955. FIELD STUDIES WITH WATER-SOLUBLE INSECTICIDES FOR THE CONTROL OF

MOSQUITO LARVAE IN CALIFORNIA PASTURES. MOSquitO NeWS 15: 139-

143, ¡llus.

(46) and XOE, J. R.

1955. CONTROL OF MOSQUITO LARVAE IN RICE FIELDS WITH WATER-SOLTTRLE

PHOSPHORUS INSECTICIDES. JOUF. ECOH. Ent. 4S : 665-667.

(47) GILBERT, I. H., GOUCK, H. K., and SMITH, C. N.

1955. NEW MOSQUITO REPELLENTS. .Tour. Econ. Eut. 48 : 741-743.

(48) GINSBURG, .J. M.

1930. STUDIES OF PYRETHRUM AS A MOSQUITO LARVICIDE. N.J. Mosquito

Extermin. Assoc. Proc. 17 : 57-72, illus.

(49) GJULLIN, C. M.

1938. A MACHINE FOR SEPARATING MOSQUITO EGGS FROM SOIL. U.S. Bur. Ent.

and Plant Quar. ET-135, 4 pp.. illus.

(.50) and CROSS, H. F.

1950. THE EFFECTIVENES,S OF SEVEN INSECTICIDES AGAINST ALASKAN MOSQUITO

LARVAE IN DIFFERENT TYPES OF BREEDING AREAS. Amcr. MoSquitO

Control Assoc. and Va. Mosquito Control Assoc. Proc and Papers

1950, pp. 75-77.

(51) HEGARTT, C. P., and BOLLEN, W. B.

1941. THE NECESSITY OF A LOW OXYGEN CONCENTRATION FOR THE HATCHING OF

AEDES MOSQUITO EGGS. .Tour. Cell, and Comi)ar. Physiol. 17: 193-202.

(.52) and ISAAK, L. W.

1957. PRESENT STATtrS OF MOSQUITO RESISTANCE TO INSECTICIDES IN THE SAN

JOAQUÍN VALLEY IN CALIFORNIA. Mosqulto News 17 : 67-70.

(.53) IsAAK, L. W., and SMITH, G. F.

19.53. THE EFFECTIVENESS OF EFN AND SOME OTHER ORGANIC PHOSPHORUS

INSECTICIDES AGAINST RESISTANT MOSQUITOES. MoSqultO NcWS 13 :

4-7.

(54) and PETERS, R. F.

1952. RECENT STUDIES OF MOSQUITO RESISTANCE TO INSECTICIDES IN CALIFORNIA. Mosquito News 12 : 1-7.

(55) and PETERS, R. F.

19.56. TESTS WITH AERIAL SPRAYS OF MALATHION FOB THE CONTROL OF

MOSQUITOES. Mosquito News 16 : 84^86.

(.56) WILSON, C. S., TRAVIS, B. V., and HUTTON, G. L.

1949. THE RELATIVE EFFECTIVENESS OF SEVERAL INSECTICIDES AGAINST MOSQUITO

LARVAE IN ALASKA. MosQuito Ncws 9: 142-145.

(57) and YATES, W. W.

1946. THE SURVIVAL OF AEDES VEXANS AND AEDES LATERALIS EGGS IN NATURE.

Calif. Mosquito Control Assoc. Ann. Conf. Proc. and Papers 14:

89-92, illus.

(58) YATES, W. W., and STAGE, H. H.

19.50. STUDIES ON AEDES VEXANS IMEIG. I AND AEUJES STICTICUS (MEIG.), FLOODWATER MOSQUITOES, IN THE LOWER COLUMBIA îtivER VALLEY'. Amer.

Ent. Soc. Ann. 43: 262-275, illus.

(59) GOLDSMITH, J. B., HUSMAN, C. N., BROWN, A. W. A., and others.

1949. EXPLORATORY STUDIES ON THE CONTROL OF ADULT MOSQUITOES AND

BLACKFLIES WITH DDT UNDER ARCTIC CONDITIONS. Mosquito News 9 :

93-96.

(60) GRAHAM, .7. E., REES, D. M., and EDMUNDS, G. F., .JR.

1953. A SEASON OF MOSQUITO CONTROL WITH HEPTACHLOR. Calif. MosquitO

Control As.soc. Ann. Conf. Proc. and Papers 22: 21-22.

(61) HA UFE, W. O.

1954. THE EFFECTS or ATMOSPHERIC PRESSURE ON THE FLIGHT RESPONSES OF

AEDES AEGYPTI (L.). Bui. Ent. Res. 45 : .507-.526, illus.

(62) HEDEEN, R. A., and KEEGAN. H. L.

19.52. THE USE OF LINDANE AND DIELDRIN AS MOSQUITO ADULTICIDES IN ALASKA.

Mosquito News 12 : 242-243.

(63) HERMS, W. B., and GRAY, H. P.

1944. MOSQUITO CONTROL. PRACTICAL METHODS FOR ABATEMENT OF DISEASE

VECTORS AND PESTS. 419 pp., illuS. N.Y.

(64) HiNMAN, E. H. . T

1930 A STUDY OF THE FOOD OF MOSQUITO LARVAE (CULICIDAE). Amer. JOUr.

Hyg. 12: 238-270.
84 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

HOCKING, B.

1952. AUTOLYSIS OF FLIGHT MUSCLES IN A MOSQUITO. NATUFC 169 : 1101.

1952. PROTECTION FROM NORTHERN BITING FLIES. Mosquito News 12 : 91-102.

1954. FLIGHT MUSCLE AUTOLYSIS IN AEDES COMMUNIS (DEQEEB). MosquitO

News 14: 121-123, illus.

RICHARDS, W. R., and TWINN, C. R.

1950. OBSERVATIONS ON THE BIO.NOMICS OF SOME NORTHERN MOSQUITO SPECIES

( CULÍCIDAS : DÍPTERA). Cañad. Jour. Res. (Sect. D) 28: 58-80, illus.

HOFFMAN, R. A., and LINDQUIST, A. W.

1952. RESIDUAL AND SPACE SPRAYS FOR THE CONTROL OF SNOW-WATER AEDES

MOSQUITOES IN CAMP AREAS. Mosquito News 12 : 87-91.

HOPKINS, D. M., KARLSTEOM, T. N. V.. and others.

1955. PERMAFROST AND GROUND WATER IN ALASKA. In Shorter Contributions

to General Geology 1954. Geol. Survey Prof. Paper 264, 205 pp.,

illus.

HORSFALL, W. R.

1956. A METHOD FOR MAKING A SURVEY OF FLOODWATEE MOSQUITOES. Mosquito

News 16: 66-71, illus.

HUSBANDS, R. C.

1952. SOME TECHNIQUES USED IN THE STUDY OF AEDES EGGS IN IRRIGATED

PASTURES IN CALIFORNIA. Mosqulto News 12: 145-150, illus.

HUSMAN, C. N.

1949. SPRAT EQUIPMENT FOB O-4 7, UC-64 AND L,-5 AIRPLANES. Mosquito

News 9 : 166-170, illus.

1953. A LIGHT, PNEUMATIC SPEAYEE FOB INSTALLATION ON VEHICLES. MOSquito News 13 :134-138, illus.

JACHOWSKI, L. A., JR., and SCHULTZ, C.

1948. NOTES ON THE BIOLOGY AND CONTROL OF MOSQUITOES AT UMIAT, ALASKA.

Mosquito News 8 : 155-165, illus.

JENKINS, D. W.

1948. ECOLOGICAL OBSERVATIONS ON THE MOSQUITOES OF CENTRAL ALASKA.

Mosquito News 8 : 140-147, illus.

and HASSETT, C. C.

1951. DISPERSAL AND FLIGHT RANGE OF 8UBABCTIC MOSQUITOES MAEKED WITH

RADIOPHOSPHORUS. Canad. Jour. Zool. 29 : 178-187, illus.

JONES, R. W., Ill, and HOLTEN, J. R.

1949. JEEP EXHAUST VENTURI AEROSOL. Mosquito News 9: 161-165, illus.

KELLER, J. C, and CHAPMAN, H. C.

1953. TESTS OF SELECTED INSECTICIDES AGAINST RESISTANT SALT-MARSH MOSQUITO LARVAE. Jour. Econ. Ent. 46: 1004-1006.

KNIGHT, K. L.

1948. A TAXONOMIC TREATMENT OF THE MOSQUITOES OF UMIAT, ALASKA. U.S.

Nav. Med. Res. Inst. Rpt. No. 2,12 pp., illus.

1951. THE AEDES (OCHLEROTATUS) PUNCTOB SUBGROUP IN NORTH AMERICA.

Amer. Ann. Ent. Sec. 44: 87-99, illus.

KNIPLING, B. F., GJULUN, C. M., and YATES, W. W.

1943. A NEW OIL-EMULSION MOSQUITO LARVICIDE. U.S. Bur. Ent. and Plant

Quar. E-587, 4 pp.

MCDUFFIE, W. C, SHARP, J. F., CROSS, H. F., and others.

1949. THE EFFECTIVENESS OF PREHATCHING TREATMENTS FOR THE CONTROL OF

ARCTIC MOSQUITOES. Mosquito News 9 : 51-56.

MARSHALL, J. F.

1938. THE BRITISH MOSQUITOES. .341 pp., iUus. London.

MATHESON, R.

1944. HANDBOOK OF THE MOSQUITOES OF NORTH AMERICA. 314 PP., IUUS.

Ithaca, N.Y.

NATIONAL DEFENSE RESEARCH COMMITTEE.

1945. DEVELOPMENT OF AN EXHAUST DDT AEJROSOL GENEnjATOR FOE THE % TON,

4 X 4 TRUCK ("JEEP") . OSRD No. 6301, NRC Insect Control No. 139.

41 pp., illus.

NATVIG, L. R.

1948. NORSK ENTOMOLOGISK TIDSSKRIFT. SUP. I. CONTRIBUTIONS TO THE

KNOWLEDGE OF THE DANISH AND FENNOSCANDIAN MOSQUITOES. CULIciNi. 567 pp. Oslo.
THE MOSQUITOES OF ALASKA 85

(88) NIELSEN, E. T., and GRèVE, H.

1950. STUDIES ON THE SWARMING HABITS OF MOSQUITOES AND OTHER NEMATOCERA. Bul. Ent. Res. 41: 227-258, illus.

(89) PETROF, I.

1900. POPULATION, RESOURCES, ETC., OF ALASKA. [FROM U.S. CENSUS REPORT

OF 1880.] In Compilation of Narratives of Explorations in Alaska.

56th Cong.. Ist Sess., Senate Rpt. No. 1023. 85« pp., illus. Wash.,

D.C.

(90) PRATT, R. L.

1949. WEATHER AND ALASKAN INSECTS. Off. of the Quartermaster Gen.,

Mil. Planning Div., Res. and Devlpmt. Branch, Environmental Sect.

Climatic Res. Lab. Rpt. No. 156. 25 pp., illus.

(91) RAFFERTT, J. J.

1900. FROM PORT VALDEZ TO COPPER RIVER, DOWN THAT RIVER, THENCE TO PRINCE

WILLIAM SOUND. In Compilation of Narratives of Explorations in

Alaska. 56th Cong., 1st Sess., Senate Rpt. No. 1023. 856 pp., illus.

Wash., D.C.

(92) RALET, T. G.

1947. CALIFORNIA GROUND THERMAL AiaiOSOL GENERATOR. MoSquitO NewS 7 :

58-63, illus.

(93)

1952. THE PLUMBER'S NIGHTMARE, KING SIZE. Mosquito News 12: 141-144,

illus.

(94) RAYMOND, C. P.

1900. EECONNOISSANCE OP THE TUKON RIVER, 1869. In Compilation of Narratives of Explorations in Alaska. 56th Cong., 1st Sess., Senate

Rpt. No. 1023. 856 pp., illus. Wash., D.C.

(95) Ross, E. S., and ROBERTS, H. R.

1943. MOSQUITO ATLAS, PT. I. THE NEARCTIC ANOPHELES ; IMPORTANT MALARIA

VECTORS OF THE AMERICAS AND AEDES AEGTPTI, CULEX QUINQUEFASCIATUS. 44 pp., illus. Phila.

(96) ROTH, A. R., YATES, W. W., and LINDQUIST, A. W.

1947. PEELIMINABT STUDIES OF LAEVICIDES ON SNOW-WATEE MOSQUITOES.

Mosquito News 7: 154-156.

(97) SMITH, C. N., GILBERT, I. H., and GOUCK, H. K.

1958. USE OF INSECT REPELLENTS. U.S. Agr. Res. Serv. ARS-33-26, rev.,

6 pp.

(98) STAGE, H. H.

1951. MOSQUITO CONTROL AGENCIES IN THE UNITED STATES. Mosquito News

11: 8-22, illus.

(99) and CHAMBERLIN, J. C.

1945. ABUNDANCE AND FLIGHT HABITS OF CERTAIN ALASKAN MOSQUITOES, AS

DETERMINED BY MEANS OF A EOTABY-TYPE TRAP. Mosqulto News 5 :

&-16, illus.

(100) GJULLIN, C. M., and YATES, W. W.

1937. FLIGHT RANGE AND LONGEVITY OF FL0ODWATER MOSQUITOES IN THE LOWER

COLUMBIA RIVER VALLEY. Jour. Bcon. Ent. 30: 940-945, illus.

(101) STEFANSSON, V.

1921. THE FRIENDLY ARCTIC. THE STORY OF FIVE YEARS IN POLAR REGIONS.

784 pp., illus. N.Y.

(102) STIVERS, J. O.

1956. PHOSPHATE USE IN CALIFORNIA MOSQUITO CONTROL. MOSqultO NewS 16 :

87-91.

(102a) STONE, A., KNIGHT, K. L., and STARCKE, H.

1959. A SYNOPTIC CATALOG OF THE MOSQUITOES OF THE WORLD (DÍPTERA,

cuLiciDAE). 358 pp. Entomological Society of America, College

Park, Md.

(103) TRAVIS, B. V., APPLEWHITE, K. H., FRITH, G. R., and GOLDSMITH, .T. B.

1953. ADDITIONAL OBSERVATIONS ON THE CONTROL OF MOSQXHTO LARVAE IN

ALASKA WITH DDT. Mosqulto News 13: 1-3.

(104) APPLEWHITE, K. H., and SMITH, N.

1950. CONTROL OF MOSQUITO LARVAE IN ALASKA WITH DDT. JoUr. Econ. Ent.

43: 350-353.

(105) GJULLIN, C. M., BLANTON, F. S., and others.

1949. PEEHATCHING TREATMENT FOR THE CONTROL OF AEDES IN ALASKA.

Mosquito News 9: 42-48.
86 AGR. HANDBOOK 18 2, U.S. DEPT. OF AGRICULTURE

(106) TuLLOCH, G. S.

1034. MOSQUITO INVESTIGATIONS IN ALASKA.. Psyche 41: 201-210, illus.

(107) UNITED STATES DEPARTMENT OF AGRICULTURE, ENTOMOLOGY RESEARCH BRANCH.

1955. INSECTICIDES AND REPELLENTS FOE THE CONTROL OF INSECTS OF MEDICAL

IMPORTANCE TO THE ARMED FORCES. U.S. Dept. Agr. Cir. 977, 91

pp., illus.

(108) VANNOTE, R. L.

19.54. EXPERIENCE WITH GRANULAR INSECTICIDES FOR MOSQUITO CONTROL IN

EASTERN UNITED STATES. N..J. Mosquito Extermin. Assoc. Proc. 41,

pp. 123-126.

(109) VOCKEROTH, J. R.

1954. NOTES ON THE IDENTITIES AND DISTRIBUTIONS OF AEDES SPECIES OF NORTHERN CANADA, WITH A KEY TO THE FEMALES (DÍPTERA : CULICIDAE) .

Canad. Ent. 86: 241-255.

(110) WASHBURN, G. E.

1954. EXPERIENCE WITH GRANULAR INSECTICIDES IN THE WESTERN UNITED

STATES. N.J. Mosquito Extermin. Assoc. Proc. 41, pp. 118-123.

(111)

1956. GRANULAR PESTICIDES IN CALIFORNIA MOSQUITO CONTROL. MosquitO

News 16:104-105.

(112) AVHITEHEAD, F. E.

1951. RICE FIELD MOSQUITO CONTROL BY PELLET-BORNE INSECTICIDES. Ark. Agr.

Expt. Sta. Bui. 511, .30 pp.

(113) WILSON, C. S.

1950. AEROSOL SPRAY UNITS FOR CONTROL OF BITING INSECTS. MOSQUITO NCWS

10: 51-54, illus.

(114)

1951. CONTROL OF ALASKAN BITING INSECTS. U.S. Pub. Health Rpts. 66:

917-922.

(115) WRAY, F. C.

1946. SIX GENERATIONS OF CULEX PIPIENS WITHOUT A BLOOD MEAL. MOSQULTO

News 6 : 71-72, illus.

(116) YATES, W. AV.. and GJULLIN, C. M.

1947. PRE-HATCHING APPLICATIONS OF DDT LARVICIDES UN FLOODWATER AEDES

MOSQUITOES. Mosquito News 7 : 4-6.
Appendix

ipQ' is£ is:'

= cr'^

OCEAM

x>^

ALASKA

• Aedes conununis

"(..-

rJ'^^'*»

c A ^,

MAP 1.—Distribution of Aedes communis.

87
88 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

'<^- >"' >tO- W IS2- P*«- ,W 140- 13b- ur 138- (2Í.' 120- ' \ \ \ 1

^ry'^'^^^'^^^^^ ALASKA

A ?■■' \ ,_-^ ^° " ° ° K 5 /(R A N 0 t ( >U .-»•

I / ) / ^^"""^-^^ ' ^'\î

"^/fecW^'l^ • Aedes punctor

. -^ ' ^." V^f «.^p ^-»-/^ - - ^?îll^c;( "L-^ A-i, •

' / R^ '"""'"'" wP^ i???C- ';:^„ '

^iw- y---- ^ ^ ^ j^^s^y'^ ^^tiji^^^ ^~"^i

*, ^^^^C^ '^"'^Ç^/'^Zil^^^^ "^ ^^^^^^--l /WLkonW, ^"S^'f,

fOi/A-oU ^^ _ M,«.-*^ ^^a D,iu ''^'^i-Ci

i<y\_^f!^4/ J-, / "'¿A '"'•'^''^j-vi/ "'° ^ u

/~^J ....:7ri '".'^v/ ^"^'-"^ '"•-£ wSsit Á k. W »ló.t-rl^y^VS ^ ^"- / ^h flby^^"" ' ^^

t J ^^ -——^ / ^ ' ^ if CuikjJJr *• '\

V/? ^^^—---/'^^ 'i^ M JL>—irtf^^tr"'^"'" '

- Iff

J <A, /^ \, ^ y^Br^^^GA ^^fC^ ^

-

\I} Xt f /-/ jsC^-^'äS^^M''*'^"-. ;

> ^K/^r&^^^^^~~^~^S}--'^:

•K

^¿iS^^^v 1 0^*^ .r^ yy^'-r-" ' ' "' ífu/^-*'*^ /4 (*^ r^^ ry^C^YLoà-^y 6a.o-.inÇ^M/^^3^-.^^

--« ^^ÜJA ^¡J^ P A C/ ^' ^ ° ^ Í

' '' ""^^^tó "^ '

/"^^x^r^ '^ ^^fc

J 1)?LAí^ Jin'-''' , r , ,

^AS ,-

'" '" "•

.0.

MAP 2.—Distribution of Aeies punctor.
THE MOSQUITOES OF ALASKA 89

^cr''

i^o' \3t- ij;- izt- I;í,-

o r c.^ /v

X>'.

s / R A N G t

IT ,oV zjRiyi -

ALASKA

Aedes implicatus

I KLAS^/J

'^

V

O"-

.\->

. \%

p A

I F I C 0 C E

MAP 3.—Distribution of Aedes implicatus.
90 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

11,0- I'...- rs." («6- i^,.- 140- Lit ;j;- ,;.- i¿..- ijr,-

,.^S^2^ OCEAN

N>"'" 'V^T^ ^V->^

/ ^J A'^\">

ALASKA

./ ' "Cr'

X .' \ ^^^"''"»^S/IR/VNOÍ >l. ...-

\ /

\ /^^- î\î

> '' '-

cA ',1 Aedes cinereus

- .'"'i-"-'(fc^^^'S- Vb^"L..,,,,^?î^t'-'-'-- A diantaeus

^^ • pullatus

.'' , ^^' '•

^^/^ >TiCwCt- ^^>^^\-f- 6/,'

.'*" ^

' "'''InI... ;;.'.-

^ '»ru

)- r^'-"-^^^^"^^ ^^Y^^^^""^ "'"'^Y^^,,, ^ït

>.>^

// ' M't-iiv*:^ ? \.^Y '"'-* ^^ r^V

, la*

X ,-

^

—^ í \LíT!|%J-,- ';

. bO>

"^ Y r /iM^hX^:;%

'

-^— -i^fer ^6^^/ •'** Si'Xg^^

/n-^¿^TT*"^ \55^^ ° ^

r-^/^ 1 i 1 1 ^_ j_ - 1

MAP 4.—Distribution of Ae(?;e.s cinereus, diantaeus, and pullatus.
THE MOSQUITOES OF ALASKA. 91

MAP 5.—Distribution of Aedes excrucian^ and intrudeuii.
92 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

^ „f.- bO* PSh' ps:- Ifc8* 14..- IfcO- 136- JJ2- i:a* iza' izo-

^^--^l'^^^ OCEAN '

sPf"''x^ /\

^ ^V-^

^^^J^R^^: ALASKA

/ ""tsl

° " ° 0 K 5 /(R A N 0 t tU ^w

\;/.'^'-^-".^.b^^ * . I

• Aedes pionips

A Stimulans V^r^'X^^- 7^--V ^^ Li?^ ,.,,..>.^r^j^^^.\'''''

-w

"/ ^"° "'"""

^l^llliaCtt V^-^^ "V^^ J

0.

VC/!^" J i _^ 'Xy«'''^^ ^"~^ ^^^'''""~\:qÉí%r" '3

^ w

XTi^y^^'// r- ^ *'"l¿a'^'-^^'^T^W.T^ / «^o

y ) A~,.k// ,' ..;;W\^ />.--j ^'""fiJß- ^<^

f J^~^^ -^

"N '"' "W^i^fe"''' >

vr

-^ !5'^^?^'"^ /^' ^^'33l^V^.-.. \_ ^\2/P^^/^ ^^"% vt

f ^.^ Cl.ll,",t¡um/^ ,

^êœ"^ XTí 1 rai-.SS ~-.>

(^»-^^ <^ , ,c> f

Í /I A/ "' M ü*^/íá-'

.^-->¿í*^í> p^ rfl'>

, \tó\f/

/^Si>T^ /»°"-' 1 1 1 1 1

^^

"'

MAP 6.—Distribution of Aedes pionips and Stimulans.
THE MOSQUITOES OF ALASKA 93

^^ '^- ~

.sBC^'^^

-"•'.....J'' ^i^ ^;£ 1^^ T ^i— \iZ- IZS- l¿'.' 120'

K> -•>f/k''^r^> ALASKA

/ ',...Z^

^ ^' ^^"^

' " ° ° « 5 /R * M 0 t 1 >|, . b*-

"^ '^^v ' ii°

c-o \/;'''-'-'',,_,.,,,bk__ ^ 1 •* • Aedes cataphylla

flavescens

A hexodontus "/ %^s^:::: i-^'!^."°!^i^C^~4 ^ riparius

^^'^To^ S //^^Ji3--- u^^,.^rl.. -;; 1

^°OA,ß V^^£J ^ 7» ^*=«aO'ii- "/^

-

(T (—--^ ^3^ T^"" ^L^¿^--' SiCr

v. T y iJ3r^ c1ii/(j. p\civi.~o \

-'^M^pu-^"^^ \^ jj:^'3^^-'.rl,, \

f_^i o.»..,k.~/^ ^

^Ji^sj^^<--^e-v/'^^^

Iff <!''5^\A¿;^ ^^ U^ V~*^ j( ^ N/^^Vl^C^f N-^

•to cuiroF»'-* c«!Il^X^^!^5Îiv^°v^.

/ .^' ^ ¿>'-'- ''*'" )fc\i'/^'^

V^ P A f ' ^ ' "^ " ' '

.. "°'"'"H^Ä^-r""

y^-^^ly fi^ ^\^^\'

^yjT^^^v^ VÖÄ * ^^

j—VILAI^ a>'-'-"-

.S2' !*« 1*4-

MAP 7.—Distribution of Aeies cataphylla, flavescens, hexodontus, and riparius.
94 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

.!«• ibO- If.»,' (52* \^ff l.t- 1*0- I3b- 122- 128- r24' 120'

.^B^'"

^_^¿^Jn_^ OCEAN

\ \ \ V

C^ ^\K->^ -.^J?^^^ ;

ALASKA

/ ' '" " vvL ^ , ?/„' \ .^_ ° " ° 0 K s /(R A s 0 t >!, ^w

\ / " A / ^^"^-~- ' '.\°

V /-'•'/,'. ,.„.}>i-, . ': „.. .!^.; • Aedes fitchii

i^^^^^^r^rr: \J7^ ,..,.^^:¡¡^^-\-'-''-^-

A impiger

• "/ ^fc,*° "'-".s.,< r^y íí?'^''^ c--^' '

- w

.. C^, ^,.......

»-'Z^^ -p>'^t:!::^ W^- '^'i

"""O^,,!

- w

ijj^^'^ ^ /

-i^^ /

/

Í*-' ,*^ -¡**7 ^^.-7 ^tf^'^Wt^''« V ^/'Z^S, \3 /^ I '-'"U

S/ i_'~^^ / V Vi 1] .>-^^ c .^ ', „y^^^-V "0 \/i-^rf*—'^^^ ^isT" " I

> u-

/ "vA t^ y ^ ' Y aP ""'' ^cjfy^-

- '\2¡ \ß 'P^"^ "^ J^^^S"^^^'^^ \

) /¿y^h'i^j'''^—^-^$x'/'^X'

-6^^^J^^iL v-^ ,„.,„. .••'^"

Ch«ha^lL, -»Jv^lövV ^?*-

/ ,-' y />••' •" ' ""'^^C**» f JT t^ S

/ ^ v'^ ^^•^

y^P^^ ..c-^'^ '" '""^^^¿s'^r

y—>4^1>^ <i^ ^@^

/—VstAr'^'^û»^^' 1 t 1 1 \

.. "* '" "* '*"

i-o- iw ij;-

MAP 8.—Distribution of Aedes fitchii and impiger.
THE MOSQUITOES OF ALASKA 95

ALASKA

Tundfo.bor« rock.A ic.

CZ) M.r,.rbor..l(or„,

HH Coaltar for«st

O Aedes aboriginis

canadensis

** decticus

nigripes

Culex territans

MAP 9.—Distribution of Aedes aboriginis, canadensis^ decticus, nigripes, and

Culex territans.
96 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

MAP 10.—Distribution of Anoplieles earlei and Culiseta tnoraitans.
THE MOSQUITOES OF ALASKA 97

i : '^ 'SlL '0°' IS-- IS;- 1-S- I«-- CO- uf M" i-H- '¿••' l-il' —T h ' • —1

ALASKA

\ I'-' \/-^-->! " ° ° K 3 /(R . N 0 t |, ^w

'^/fti:!^ .^|...-

• Culiseta impatiens

.'^' v' Vf'''4i,p ^-^-/^ _;L^'TïitÎir,r 'V^'A.Í, ; V'-

,..'•''"' ^.."I'-- 1"^'i»^^-^^^^-^»

K,,, '^'^ "^'Mi:^^^^-'---'''^'^*^,^ '-n

, w*

/~\) .. i/f^ "•i'Ä<^ ^ '-^Y '—\ ^^*\!î

r^ _V^ *"' V V'"°7\\ * ^''"/ ^^ I ^<i'j" ' X^

Ç i ^^ ^ f \ '^* K G.lkaw ^ \

H^/? ^^^-^-^'^^ '^ ^ ILp •"^^yef'^"'- •

60-

} vK . t, , / \, ^ Y^Sf '^^'^(¡Ar J^^^T'

'"Xl} X^ /^ _^ ,<á¿?|'í^^í^^^"'^'-'«5 \

{f ^J\ y^~^'— y\^ti*''0' fir T Ä^C(Wdova k,-^' _.-—'"

) /^/iF~^- "V'^^—'^.'Si /'-I^N"'

V /^ C~—i^f Msmfï^ v' '*N^^ \,',M. k \^ "^

^"^^^^^eC*^* ^ /*^^-^ j-^ ^ Ch-ft-a^lL- "•»M^>V^^ '^T'»-

/ v*" J" y_S"T"'* '

'''""''>JV^j\'j^ î^

/ ^<^ tyrr^~i'^ 6=.o-..f;^W^l^^^^

/^-{s^ ^^^ p A c / ^ ' f ° ^ ^ ^ ^ """^^^tó.r

^—s ¿v~'' .5^"^ *^** ^''í?^ ' y''^Z>"3>7r*-^ *^^Ä ^ V

r^^TjfJk.y^'^^'^-^ ,1^1 ^ 1

t, tL- n»- isa- i*a- J**- „O- 116- IJ.--

MAP 11.—Distribution of Culiseta impatiens.
98 AGR. HANDBOOK 182, U.S. DEPT. OF AGRICULTURE

"" I-.'- I„W- lo,' IbO* 156' I5Ï* 1*8' I*".' ihO- iJb' IJ2* ire* IZ*.' IZO*

^^'""/C^ ^VT^TT*-"*^ ALASKA

Ir.-

0 K s /^R ft N 0 ^ tU '"•

., 1 Xj.\ m Culiseta alaskaensis

\ I y^""" üSÍ^^^ ^ incidens

-' LIT ,..,^^^;;^--\---'--- ^ particeps

"/ ^"^'^-- ^^ J¿Í|5^^^

Hin.nJjjg"^ \^ ^"íí/>

(M^^

MT

/ r /

^^% "

/<^ f A <:'''' '' ° '^ ^ * N ^tóüP'J''

/-^k-'"iy ^ ^^^"w

j—iJj£Ar^*^" ' '

"•

MAP 12.^Distribution of Ctiliseta alaskaensis, incidens, and particeps.

U.S. GOVERNMENT PRINTING OFFICE : 1961 O— 551810