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The
appearance of
Anophelines.
search in a freshly whitewashed house. Even in places which appear
favourable, Anopheline mosquitoes are often difficult to detect, and some
species hide among the straw of a thatched roof or in holes and corners of
the wall with great success. For searching the roof a ladder should be
used, so that the eye is not more than a foot or so off the roof, and every
part of the thatch should be carefully examined. Two characters of
Anopheline mosquitoes are of great service to the collector ; they are (1) the
structure of an Anopheline is such that an imaginary line drawn along
its proboscis and through its head, thorax and abdomen is practically
straight, and for this reason it happens that if an Anopheline is resting on a
wall with the tip of its proboscis touching the wall the hinder end of the
insect projects outwards so much that the insect appears to be standing on
the tip of its proboscis. Thus, in a dark outhouse or hut the commoner
Anophelines (which are light coloured) stand out against the dark back-
ground of dirt and soot, looking like little white thorns stuck in the wall or
hanging from the roof. On the other hand an imaginary line drawn through
the proboscis, head, thorax and abdomen of any other mosquito than an
Anopheline would not be straight, but would slope upwards to a point near
the top of the thorax and then downwards to the end of the abdomen, thus
forming an angle. For this reason when such a mosquito is resting on
a wall with the tip of its proboscis touching the wall the anal end of
the abdomen is also nearly touching the wall and the insect appears " hunch-
backed." (2) As a general rule most Anopheline mosquitoes have spotted
wings whilst the wings of most other kinds of mosquitoes have no spots.
How to mount, examine and identify adult Anopheline mosquitoes.
The mosquitoes that have been caught should be killed by placing a
drop or two of chloroform on the muslin cover of the bottle. The dead
mosquitoes are then turned out on to a clean white sheet of paper and
mounted as quickly as possible.
The following articles are necessary for mounting a mosquito -
(1) A supply of fine silver pins, No. 20 size.
(2) A pair of forceps for holding the pins.
(3) Small discs of thin cardboard.
(4) Ordinary pins.
(5) A box in the bottom of which a layer of cork or pith is fixed.