100 



MOSQUITOES 



wriggle up to the surface, it drowus. Feeding as it does 

 at the bottom upon the heavier particles which sink, its 

 specific gravity is explained. The larva of Anopheles 

 77ucculipen?iis, however, habitually remains at the surface 

 of the water. Its breathing tube is very much shorter 

 than that of Culex, and its body is held not at an angle at 

 the surface, but practically parallel with the surface and 

 immediately below the surface film, so that portions of 

 its head, as well as its breathing tube, are practically out 



Fig. 18. — Young liarva ot Anopheles macuUpennis ; enlarged. 

 (Author's illustration.) 



of the water. Its head rotates upon its neck in a most ex- 

 traordinary Avay, so that the larva can turn it completely 

 around with the utmost ease, and feeds habitually with 

 the under side of the head toward the surface of the 

 water, whereas the upper side of the body is toward the 

 surface. In this customary resting position the mouth 

 parts are working violently, the long fringes of the 

 mouth-parts causing a constant current toward the mouth 

 of particles floating on the surface of the water in the 

 neighborhood, which thus gradually converge to this 



