178 



BLACK-FLIES. 



This Species is found active during the whole summer and 

 autumn, but only in certain places, which can, however, be 

 very far from the breeding-places, and these insects must pos- 

 sess some very powerful senses to detect their victims such 

 long distances. 



In our lake regions we find a large number of streams 

 that flow over rock^^ bottoms and are obstructed by floating 

 grasses, and other submerged plants. When we see a place 



Fig. 14:6.-Simuliumi)-rilat(im. n. s. Female and eggs. Greatly enlarged. Original. 



in which the water flows more rapidly than in others, we 

 can be certain to find there the early stages of buftalo-gnats. 

 By investigating the plants that cause an obstruction, we 

 find large numbers of larvae and pupae fastened to them. In 

 the more central part of the state we find the adults, illus- 

 trated in figs. 143 to 146, (the former showing a male, the 

 latter a female) the most common species, while in the 

 northern rivers the species illustrated in figs. 147 to 151 is 



