158 INSECT LIFE. 



enlarged, and Fig. 129 represents an antenna much 

 more enlarged. The peculiar venation of the wings 

 is sufficient to distinguish black- 

 flies from all others. 



The Black - flies {School 

 Work). — Prepare for your collec- 

 tion as complete a series as pos- 



FlC. 128. ... r . 1 1 • /T , I 



sible of the different stages of 

 these msects, pinning the flies and preserving 

 the eggs, larvae, and cocoons with pupae in alcohol. 

 Place them with other Diptera under a copy of the 

 following label : — 



Family Simuliida; (Sim-u-li'i-dae). 

 The Black-flies. 



Watch living larvEe in a glass of water and ob- 

 serve the following : The disklike sucker, fringed 

 with hooks at the caudal end of the body. The 

 fleshy proleg situated just back of the head ; this ends 

 in a sucker fringed with hooks. The thread of silk 

 spun from the mouth. The fan-shaped organs borne 

 by the head. And the three delicate, much-branched 

 tracheal gills, which are pushed out from between 

 the last two abdominal segments. 



Write an account of what you have learned re- 

 garding black-flies, including a description of the 

 methods of locomotion of the larvae and the prob- 

 able method by which the larvas obtain their food. 

 It has been found by examining the stomachs of 

 these larvas that they feed on microscopic aquatic 

 plants and bits of tissue of larger plants. 



The Net-winged Midges {Field and School Work). 

 ^These insects occur in situations similar to those 



