120 



DISEASES DUE TO PROTOZOA 



the surface film and to bring the pupa into a good position for 

 breathing. 



The pupa matures in two days in hot weather. 



When the adult is about to emerge the pupa straightens its back, 

 the skin of the cephalothorax bursts along the back, out of which 

 opening the adult appears. It rests for a few minutes and then flies 

 away . 



Vn^pa. oi Anopheles niaculitennis, Meig. Enlarged. (After Grassi.) 



Soon after a female is hatched it probablv becomes fertilized; some 

 maintain that it takes blood first; oviposition follows the blood meal, 

 and takes place in the earlv morning. 



The time of development is (average) : — 



Egg stage 

 Larval ,, 

 Pupal ,, 



I to 



7 „ 



•7 



i8 



days 





lo to 24 days, or longer 



BIONOMICS. 



The imago emerges from the pupa during the late afternoon when 

 the female is ready for fertilizing the male. The latter sex usually 

 predominates numerically. 



The female alone bites man and animals in order to obtain blood, 

 which forms rich food for the eggs, but much more rarely they will 

 feed on juices, the Culicinie more than the Anophelinaj. 



The mouth parts of the female alone are adapted for piercing. 



It is during this act that malarial sporozoites are injected into the 



