Delaware gazette and state journal. (Wilmington, Del.) 1883-1902, 1900-08-09
HOW MOSQUITOES WORK.

Scientists have for years been study
ing the disense germs taken by mos
quitoes from one human being, de-
veloped in the body Of the insect and
then injected into another Ierson to
poison his blood with malaria, but few
have given much attention to the study
OF the poison generated by the mosquito
itself and injected into the victim of
his, or rather her, bite. Tho effects Of
this poison are apparent every day in
the lblotches, and sometimes slight
which surround the scene
of the mosquitoes blood sucking visit.
DR.. w. 5. Thayer, who at Johns
Hopkins Hospital is engaged in series
OF experiments which carry out the
now accepted theory that mosquitoes
transmit malaria, says that he knows of
no scientific investigation of the mos.
quito poison which accompanies every
bite inflicted by the insect. So wide
spread are the ravages of the mosquito
that nearly everyone is acquainted by
personal contact with the contents Of
the poison gland of the little insect.
With the bite comes a singing sens8-
tion OF greater or less intensity, accord
ing to the susceptibility OF the person
suffer- ing It, Itching follows, which is
usually allayed by scratching the bite.
Heie 10 where, the damage is done
according to. some physicians. From
the scratching finger nail germs get
into the slight wound and these set up
az irritation and local inflammation
which may result in the formation OF
little pustule.
1t Is believed that the actual poison
OF the mosquito, which is really it's
saliva, is only slightly irritating
organic poison which would have no
bad effects upon the human system, its
irritating influence soon wearing away
But the finger nail does the work by
introducing germs into the tiny wound.
So minute are the little poison glands
and so email is the amount of poison
secreted by the insect that no one
has taken the trouble to gather it
in quantity sufficient for chemical
analysis.
The function Of the mosquitoes
poison is probably two-fold Some OBJ
servers think it Is injected to and lubri.
eating the proboscis as it sis inserted
in the skin to secure the insects meal
Of blood. Another theory is that the
poisonous saliva serves to make more
fluid the blood, so that it may be more
easily sucked out by the mosquito.
This seems to be borne out by the
noted absence of irritation from the
poison If the mosquito is allowed to
suck his fill, as then the poison is Irob.
ably sucked out also. If the mosquito
is interrupted in its meal the full
effects of the poison are felt.
DIR. John 8. Fulton, secretary of the
State Board of Health, says that when
living in a mosquito infected section
of Maryland he tried not to mind the
little pests, allowing them to have
their feasts oil his blood undisturbed.
Soon, he says, he became immune to
the poison and po longer minded the
bites nor was he Inconvenience by the
punctures Of the mosquitoes.
While Baltimoreans are rising in
their wrath these warm nights to smite
the pestiferous mosquitoes that are
yards they may be interested to know
lust what they. are shifting or would
like to smite. In the first place it Is
the female of the species that has the
bloodthirsty propensity.
The taste for bluod is supposed to be
largely acquired. for it would obviously
tb tu pOnbIbio LUZ dll iuuSquibObo 10 1851
on warm FLOODED animals. Their regu-
lar diet is a vegetable one-luices
sucked from fruits and flowers Some
species have been studied which still
keep up their vegetable habits. OF
other species the females alone are
blood suckers, while the males stick
to their vegetable diet. In rare cases
species have been found in which both
h., -
The act OF biting OF mosquito has
been likened to ths sinking OF an
srtesian we'll shaft It's biting appara
tus is the proboscis. which has beer
discussed into nine parts. One Of its
principal parts is the upper lip, which
extends nearly to the end of the organ.
Beneath it and in groove Is long
pointed canula which is a sort of ex,
tension Of the pharangeal tube. Through
this the blood is sucked. On either
side are two lancet shaped pieces
mandibles and maxille, which prepare
the way for the insertion of the pro
boscls. The maxille are more delicat,
and provided at the ends with mum
Der of spine-like barbs, probably t,
enable the mosquito to hold on afte
it has once started on Its quest TO
blood. Beneath all is sheath which
incloses the other parts except alonl
its upper border when oEen. This !
the lower lip and is somewhat dilatet
at Its end into a pair of iointed valves
These probably have to do with tn
sucking OF blood.
When the piohcscis is in action it is al
forced into the skin except the sheath
which is bent into sort of loop, whicl
becomes narrower as the piercinl
organ penetrates more deeply. At eithe
side Of the base Of the proboscis is
pair of iointed appendages, maxillar
palpi. The poison Is secreted either ii
two glands, which are situated at eacl
4 side of the thorax, or in single giant
at the base of the proboscis.
The sides and front OF the head o
the mosquito are occupied by facette,
eyes. This probably accounts fot tn
ease with which mosquitoes sscap
from impending smashing under al
uplifted hand. They are able to Sc
all around them and SO are able TO ge
out OF danger. In some species tn
eyes touch each other in fronC, so com
pletely do they cover the head -
A recent work on gnats, or mos
quitoes, by Major George M. Giles, a
English Investigator, names over "a
distinct species. Of these the Guile
varieties comprise about three -fourths
These are distinguished from tn
anopheles, OF misunderstanding mos
quitoes. With the exception of tn
polar regions 1t Is said that no at a
extensive land surface on the gloh
is free from mosquitoes. In Mort
America there are no less than IL Guile
species.
As a rule the culex is soberly colored
although under tho lens he show
elaborate and beautiful marking. Mos