Localities in which Pellagra is Prevalent. 



37 



and in fields, where they constitute an important element 

 of the food of robins. 



Fig. iq.—a, maxilla; />, labium. Yellow fever mosquito larva. 



The aquatic species are generally found among dead 

 leaves and other vegetable refuse washed into streams, and 

 probably obtain their food from such sources. 



The larvae collected near Gary are like other members 

 of this family of flies, soft-bodied, leathery-skinned, cylin- 



Fig. 20.— Pupa of yellow fever mosquito, ventral and side views, x n%. 



