Evening star., 1933-02-22
/ IlANY MOSQUITO
!. TYPES FOUND HERE
e Varieties Discovered i
Survey of Chesapeake
Bay Area.
There are 28 kinds of mosquitoes with

There are % kinds of mosquitoes with
~ dely differing life histories in the
Chesapeake Bay country. according to
Sthe report of survey just made by
Or. r. c. Bishopp of the Bureau of
. Entomology.
y The survey was undertaken as pre-
,ininary to more active steps to reduce
he Southern Maryland mosquito pest,
--cpecially about the beaches. The
-roblem becomes very complicated be-
t2use of the varied habits OF the numer-
C-3s species represented.
Most abundant, Dr. Bishopp found,
we're four or five varieties Of salt marsh
1,osquitos which, under favorable con-
{, tions, may fly inland more than 40
miles and have been found as far away
rift with moderate winds. Heavy
Winds tend to keep them down.
Hatch Under Water.
The survey shows the reason for the
SEASONAL fluctuations of these irritat-
ing insects. Some Summers they are
very numerous, while in other years they
ere hardly to be found. The eggs, DR..
C,shopp said, are lain on the moist soil
tut do not hatch until they are covered
: nth water. They wait for heavy rains
or high tide. If the year is excep-
onally dry no new mosquitoes may
aDpear, but the eggs remain dormant for
wo or three years until the waters re-
urn. There are few egg layers each
ear, adding to the accumulation, so
hat wet year brings out an innumer-
able horde.
. Perhaps the most difficult to handle
Of all the mosquitoes of the Chesapeake
Say area, DR.. Bishopp and his aides
.ound, Is an insect with the aristocratic
name of Mansonia Perturbans, which
vas collected in eight localities, includ-
ng a swamp near Hyattsville. This
mosquito deposits its eggs near the roots
or underground stems OF swamp cat
tells. Both the newly Matched larvae
and the pupae attach themselves to the
roots of the water plants and obtain
enough oxygen from their hosts to keep
them alive. Thus these two important
stages in the life cycle are spent under
water. Against these creatures the
ordinary mosquito preventive measures,
such as use of oil films over the water
or insect-eating fish, will be useless.
They do not come to the surface until
they are ready to fly away.
Many taTletlcS tOun0.
The investigators trapped several va
rieties of wood mosquitoes which breed
along river banks, in ponds, or rain
water pools in the forests. These also
vary greatly in numbers between wet
and dry years. Experiments have
shown, DR.. Bishopp said, that the eggs
four years and still hatch when they
receive adequate moisture.
Many of the varieties were of So
called domestic mosquitoes which
breed near human habitations in rain
water barrels, sewage pools. old tires
and caves troughs. A serious source of
em through the whole Chesapeake
country, DR.. BiShopp found, are
IS Of flowers left in graveyards
7e are almost ideal Matching places.
iding not only water but plenty
1rganic nourishment from the de-
ng flower stems, for the larvae.
variety of yellow fever mosquito
found. Among the varieties ca
; lie of spreading malaria, one was
md here which hitherto had been
know north of Georgia.
. Only the females of any of the %
) 'arieties found in the Chesapeake Bay
. ountry bite. DR.. Bishopp says. The
. ales invariably are peace-loving,
. 2rmless creatures, asking only to be
. : alone. Two or three of the va
cites found will not bite human be-
; lg-at least no evidence could be
Il und that they ever have. They may
''te some Of the lower animals.
Used Electric Traps.
The survey was carried on by means
of electric traps devised by the Bureau
of Entomology. Such a trap consists
of a hollow cylinder, 18 inches long,
with an electric light at one end. In
side is revolving fan. The mosquito
Is attracted to the light. Once at the
'mouth of the cylinder it is drawn in
'forcibly by the suction of the fan and
dashed against an inclined screen in
sthe rear of a tube. From this screen
1T drops into cyanide jar. Sometimes
as many as 5000 insects will be caught
IN one trap in the course of night.
Such traps. however, are not considered
practical as a means Of reducing the
mesquite population, but only for find
Ing out what kinds there are to con-
tend with. This must be known before
any steps can be taken to remedy the
situation, since methods which are
effective against one variety are use
less against another
: The census was carried on in both
Maryland and Virginia by DR.. Bishopp,
assisted by F. N. Cory and Alan Stone
-of the Bureau of Entomology. The
results are reported in a communica-
ton to the chronological Society of
: washington. A similar survey has
!. been carried out in Delaware by en-
-tomologists of the Agricultural Expert
.ment Station of that State. Traps were
maintained at Chesapeake Beach. Ber-
!, lin and Ocean City. One trap also
was maintained near Hyattsville
T. r. H