DUT1-:HA ok MINNESOTA. 



39 



I! TH, 



Fig. 24. Wing of net-winged Midge. After 

 Conistiick. 



running streams. In i8q6 Willis- 

 ton li'ave seventeen known species 

 distributed as follows: Six in Eu- 

 rope, one in Asia, six in North 

 America, one in West Indies and 

 three in South America. The 

 larvae live in the swiftest water, at least one species being provided 

 with six suckers on its ventral side, evidently of use in the swift cur- 

 rent. The complete life history of any one 

 species is not known. From the fact that the 

 larvae inhabit clean swift streams, it follows 

 that these, flies are more numerous in moun- 

 tainous districts than they are in low lands. 

 The food of the larvse is said to be chiefly dia- 

 toms. The pupae are found fastened to rocks. 

 Kellogg says, in commenting on the 

 emergence of the imagoes from the pupal 

 cases, that so many are swept away before 

 their wings are unfolded or before their legs 

 can be loosened from the pupal sheath that it ^'"'g- -5- Dorsal and ventral 



^ ^ view oi the larva oi a net- 



seems no wonder that the familv is a disap- winged Midge. From Kei- 



i logg s Net-Winged Midg- 



pearing one. «s." 



DIXIDAE. 



The Dixa Midges. 



Only one genus, Dixa, is found in this family, which appears close- 

 ly allied to Tipulidac on the one hand and Culicidae on the other. 

 They are small gnat-like flies, with long, slender legs, resembling 

 mosquitoes in a general way, but quite unlike the latter in wing 



Fig. 26. Larva of Dixa. F'rom Miall's "Aquatic Fig. 27. Pupa of Dixa. From Miall's 

 Insects." "Aquatic Insects." 



structure. The species (about twenty in number) are found in 

 shady, swami)y places, and, like other midges, have the habit of 



