CULICID/E 



787 



males. These latter can sometimes be seen in large numbers, while 

 but few females are observed, which is supposed to be characteristic 

 of the breeding period. 



The female alone bites man and animals, apparently for the pur- 

 pose of obtaining rich food for the eggs, while the male feeds on the 

 juices of plants and fruits. The female can also be seen feeding 

 upon vegetable juices, though this is more common in the females 

 of the Culicinae than in those of the Anophelinse. It is believed 



I 



Fig. 392. — Diagram to 

 SHOW THE Posture 



OF AN AnOPHELINE 



Mosquito on a Wall. 



Fig. 393.— Diagram to 

 show the Posture of 

 Another Anopheline 

 Mosquito on a Wall. 



Fig. 394. — ^Diagram 

 TO show the Pos- 

 ture OF Culex pi- 

 piens on a Wall. 



(After Sambon, from the British Medical Journal.) 



that a female feeds on blood once a day in nature, but this is 

 a difficult matter to be certain about. The mechanism of the 

 bite has already been described in page 223, to which reference 

 should be made. It will also be noted that the structure of the 

 female mouth-parts is adapted for piercing, while that of the 

 male is not. It will also be remembered that only the stylets 

 pierce the skin, and that the labium never does so. Infection of 

 the victim by the malarial germ takes place during the act of 



biting, as the sporozoites 

 pass down the hypopharyn- 

 geal or salivary tube, while 

 the infection of the mosquito 

 is effected by the blood, 

 which passes from the victim 

 along the labial or blood- 

 tube into the mouth. So 

 much blood may be sucked that it may appear per anum. 



Usually the mosquitoes bite at night, and preferably in the dark, 

 as, for example, they will attack the ankles of people while sitting 

 at dinner at night. 



After feeding, the mosquitoes usually retire to a dark portion of 

 the room to digest the food. It is noticeable that they avoid 

 white areas during the daytime, and prefer dark-coloured regions 

 away from the light, and hence are very difficult to find in ill- 

 lighted native huts. 



Fig. 395. — Raft of Culicine Eggs. 

 (After Sambon.) 



