DISEASE-BEARING AMERICAN MOSQUITOES 

 WHY MOSQUITOES BITE 



19 



Mosquitoes bite because blood is believed to be a biological 

 necessity for full development of the eggs. As this necessity is. 

 only a feminine one, male mosquitoes are vegetarians, and never 

 bite. They may be distinguished from the females by the fact 

 that their antennae are more plumose — that is, more heavily 

 haired. 



'•"'W/iOft, 



Fig. 12. — Proboscis of mosquito with lancets (stilette bundle) raised out of 

 sheath. (After U. S. Public Health Service.) 



While biting, the mosquito pierces the skin of its victim by 

 means of a number of lancets which lie in the beak. As they 

 enter the skin, the beak covering bends near the middle, thus 



Fig. 13. — Proboscis resolved into stilette bundle. (After Daniels.) A, 

 labrum; B, two mandibles; C, hypopharynx; D, two maxillae; E, sheath (labium). 

 F, distal end of the sheath. 



allowing the head of the mosquito to get up close. The beak 

 and lancets are described by Headlee' as follows: 



"The beak covering, which is the only member of the mouth append- 

 ages seen by the ordinary observer, corresponds to the labium or lower 

 lip of the chewing insect. It is grooved length- wise along its upper 



1 "The Mosquitoes of New Jersey and Their Control," New Jersey Agri- 

 cultural Experiment Stations, Bull. 276, 1915-,— r 



