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of another genus and so on these grounds could group the mosquitoes in
the different genera in perhaps two or three or more sub-families.
The sub-
family
Anophelin
is most
important.
This plan of classification simplifies the subject, and at present the 700
or 800 species of mosquitoes which are known have been classified in
109 genera and 10 sub-families. It is obvious that if such a classification is
founded upon anatomical characters which are constant and easy to observe,
there should be no difficulty in ascertaining first the sub-family and then the
genus of any particular mosquito, and that since the number of species in
any genus is, as a rule, small, we ought to be able to name any mosquito
correctly without much difficulty. So far as the student of tropical medi-
cine is concerned, it is fortunate that only two sub-families of mosquitoes
(namely, the sub-families Anophelin and Culicin) are known to act as
carriers of human disease and that the members of only one sub-family, the
Anophelin, act as carriers of the malaria parasites. For our present
purposes, therefore, we have to deal with the Anophelin only, and it may
be said at once that the characters of mosquitoes in this sub-family are such
that there is no difficulty in distinguishing a malaria-carrying from a non-
malaria-carrying mosquito. In dealing with this subject we shall discuss first
the collection, examination and identification of adult Anopheline mosquitoes.
How to collect adult Anopheline mosquitoes.
One of the habits of Anopheline mosquitoes is that they fly about only
after dusk and during the night ; in the daytime they seek some dark shed,
outhouse, or stable, where they rest on the walls and roof. In these
places they can be easily caught, the necessary implements being a
few dry test tubes, a large dry bottle and some cotton wool. When a
mosquito is seen resting on the wall or roof, the mouth of a test tube is
placed very gently over it. It will fly into the tube, the mouth of which
can then be closed with a plug of cotton wool. Each mosquito caught
may be transferred to the large glass bottle by placing the mouth of the
tube over that of the bottle and removing the cotton wool plug. The
mosquito will fly into the large bottle, and the tube can be used again. If
Anophelin are at all abundant, twenty or thirty can be caught in this way
in a very short time. The best places in which to search for them are
outhouses, cowsheds, woodsheds, and thatched unoccupied rooms with
dirty smoke-blackened walls and many cobwebs. It is almost useless to