ARTHROPODA 



191 



as long as the proboscis, while those of the female are less than one- 

 half as long. Culex larvae have a slender, long siphon, and hang 

 down from the surface of the water. The adults in resting position 

 do not elevate the abdomen as in the Anophelines. Filariasis, the 

 disease known as elephantiasis, which is caused by a small nematode, 



Fig. 88. Larvae of Anopheles, above, and Culex, below, in feeding and breathing 

 position. (From Howard, Mosquitoes oj the U. S.) 



Microfilaria bancrofti, is transmitted through the agency of a Culi- 

 cine mosquito, Culex {fatigans) quinquefasciatus. Dengue, or 

 breakbone fever, is a tropical disease, found in Mexico, which is 

 transmitted by both Culex fatigans and Stegornyia calopus. 



Poison. — The poison of female mosquitoes has not been thor- 

 oughly studied, but Noguchi reports that there are three sets of 

 glands, two of which are ordinary salivary glands, and the third set, 



