6 
Mosquitoes and 
THE LIFE-HISTORY OF MOSQUITOES. 
The life of mosquitoes, as in the case of other flies, as well as 
butterflies, beetles and many other insects, is divided into four 
sharply defined stages. These are (1) the egg, (2) the larva, 
(3) the pupa, and (4) the adult insect. 
The larval period is invariably passed in water, where the 
larvae obtain their food, consisting usually of minute particles of 
animal or vegetable matter, which are swept into the mouth by 
large brush-like organs continuously kept in motion. A few 
species are predaceous, and many others, if their normal food 
supply fails, do not hesitate to become cannibals. Although 
Fig. 1.—Wing of the Common House-Gnat ob Mosquito 
('Gulex pijoiens). x about 16. 
la. —Portion of 2nd longitudinal vein, greatly enlarged, to show the covering 
of scales : (a) median vein-scales ; (b) lateral. 
lb. —Portion of hind margin of wing, greatly enlarged, to show the fringe : 
(a) border-scales ; (6) fringe-scales. 
passing their existence in water, the larvae are incapable of 
extracting their supply of oxygen from it, and consequently it is 
necessary for them to come frequently into contact with atmo¬ 
spheric air for purposes of breathing. This is effected by the larva 
wriggling to the surface of the water* and hanging on to the 
surface film by the breathing organ, which is situated at the tail 
* The only exceptions to this rule are to be found in a few very remarkable 
mosquito larvae which are specially modified for obtaining a supply of air 
from the roots of water plants. 
