DIPTERA OF MINNESOTA. 



37 



Fig. 20. Larva (on the left) 

 and pupa (on the right) of 

 the Giant Crane Fly. The 

 central figure is the pos- 

 terior end of the larva, en- 

 larged, shovifing spiracles. 

 Larva and pupa three-quar- 

 ter natural size. From 

 Kellogg's "American In- 

 sects." 



of plants, and some are of economic import- 

 ance, since they destroy the tender roots of 

 grass and grain. The terrestial larvae, often 

 called "leather jackets," are produced from 

 the egg generally laid in the ground, in some- 

 thing more than a week. The eggs are gray- 

 ish or brownish in color. The internal organs 

 are partly visible through the integument and 

 body wall, and the "worm" moves awkwardly 

 by the action of transverse swellings on the 

 body provided with small bristles. Of the 

 adults a few are wingless, one, Chionea, fre- 

 quenting the surface of snow. This fly, mat- 

 ing males and females. Dr. Lugger has cap- 

 tured in this state, about Christmas time, 

 crawling about over the snow, with the ther- 

 mometer below freezing. The drawings illus- 

 trate Chionea valga, Harr. ; Btttaco7iiorpha da- 

 zips, Fab., whose larvce are aquatic, and 



Fig. 21. Ditlaconwipha clavipcs. '\. 



