7
mouthed glass vessels covered with muslin or stopped with a plug of cotton
wool, and will soon hatch out into the perfect insect.
The subject, whether a man or a bird in a cage, is put on a bed. The ordi-
nary mosquito-netting (in good repair) used in tropical countries is suspended
over the bed and is tucked under the mattress on which the subject has been
placed. The jar of mosquitos is introduced under the netting and is opened,
thus liberating as many of the insects as we wish. For birds a special netting may
be devised.
Mosquitos gorged with blood are easily recognised at sight. They are
caught by an assistant entering the net and placing a test tube slowly over
them as they sit on the gauze. A number of tubes containing a given stock of
fed mosquitos is kept in the manner used in bacteriological laboratories for tube
cultures ; and the insects are killed by chloroform or tobacco-smoke.
Tubes containing mosquitos should be lightly plugged with cotton-wool ;
should have a few drops of water at the bottom for the inmates to drink (sic),
and lay their eggs in, and should be changed for fresh clean tubes every
morning.
The females are fecundated shortly after feeding.
Grey mosquitos fed at night remain gorged and asleep for all the next day
and night. Towards the end of the second day, however, the stomach begins to
" clear," that is the meal has bsen partly digested and partly evacuated, leaving the
organ empty. The eggs are usually laid on the third day (with grey mosquitos),
after which the insect generally dies if it has not been fed again in the meantime.
In order to keep them alive for long periods they must be fed again every two
Jays. In this manner I have kept them for twelve days ; and, even after that,
saw by the state of their ovaries that they could have lived longer. As with
other animals, feeding is necessary to their existence. In order to refeed a stock,
the test-tubes are simply opened under a mosquito-net containing a crow or
sparrows, and the insects are caught again next morning as usual
A mosquito is dissected for examination of the stomach in this manner.
A needle, held in the left hand, is passed through the thorax, the legs and wings
are pulled off, and, if necessary, the scales of the body brushed off with a camel-
hair brush. The tail is then lowered into a drop of water, salt solution or weak
formalin placed on a glass slide ; and with another needle held in the right hand,
the last two segments of the tail are partially separated and held down upon the
slide. The left hand is then moved in such a manner as to draw away the
insect. If done skilfully, the alimentary and generative apparatus will remain on
the slide attached to the last two segments of the tail. If necessary, as when
the stomach is full, the last two segments may be entirely separated and the
alimentary apparatus drawn out by the cesophageal end,
The alimentary canal consists of an oesophagus, a single sac, the stomach,
and a short, straight (?) intestine leading to the anus and containing six heart-
shaped glands near the rectum. Five long tubes, the malpighian tubes, open
into the stomach at its junction with the intestine.
The stomach is roughly about 2.5 mm. long and between .5 mm. or
1.o mm. broad when uncompressed by the cover glass. Its ends terminate
suddenly in the oesophagus and intestine respectively, the latter end being
easily recognisable by the junction of the malpighian tubes (see plate I, figure
23). Beginning at its outermost surface we have first the ramifications of the
air vessels ; next a series of parallel bands of annular and of longitudinal muscular
fibies, crossing each other at right angles and leaving square interstices (which
B 2