Entomology of the Illinois River. 267 



Family LEPTIDJE. 



Several large families, including Asilidae and Bomby- 

 liidae, follow before the completion of the Orthorhapha; 

 but nearly all of their species seem to be terrestrial or 

 parasitic in larval habit. A few, however, among Lep- 

 tidae, Empidee, and Dolichopodidae are known to breed 

 in wet places. 



C(ENOMYIA. 



This wandering genus, originally constituting the 



Coenomyiidae and placed by Loew in the Xylophagidse, 



«eety-,s most recently to be included by Comstock in the 



^eptidae, together with Xylophagus, judging from the 



i^haracters given by him for that family.* 



C. pallida Say. 



According to a note in Osten-Sacken's Catalogue of 

 the Diptera of North America, p. 43, this is the same 

 as the European species O. ferruginta^ the immature 

 etages of which have been described and figured by 

 Belingt and other European writers, having been ob- 

 tained by them in rotting poplar wood and in earth 

 about old stumps. 



At Sand Lake, in Lake county, June 15, one of our 

 assistants found an example of C. pallida in the act of 

 emerging from its pupal skin, which was sticking to 

 the stem of an aquatic plant some distance out from 

 shore, and on the following day another imago was taken 

 near the margin of Fourth Lake, in the same county. 



The pupa agrees with Beling's somewhat general de- 

 scription. I may add here that it is much like the 

 tabanid pupa in several respects, such as the propor- 

 tions and splitting of the thorax, ocellar triangle, ab- 

 ^dominal fringes, sculpture, etc. The "piracular rima is 

 broad, shining, C-shaped, the ends ^rurned forward on 

 ithe abdomen, while that on the thorax, which is scarce- 



• "Manual for the Study of Insects," pp. 418, 424, 456. 

 t Verb. d. k. k. zool-bot. Gesellsch. in Wlen, Jff30, p. 343 



