55 



of their powerful beaks. One specimen, referred to the above species, 

 was taken in the bunch-grass. Other species were seen along the 

 roadside. As much of the bunch-grass is pastured, a number of the 

 Tabanidac would be expected in the association. 



Chrysops callidus Osten-Sacken. June 20. 



One of the "deer-flies." Taken along sandy roadside. 



Anthrax sp. (undetermined). July 19, 29. 



jMembers of this family, the Bomhyliidac, are parasitic or partly 

 predatory, according to John B. Smith. Some parasitize lepidopter- 

 ous larva;; others feed on the egg-pods of grasshoppers; and still 

 others live in the nests of bees. Hart records five species of Anthrax 

 from the sand regions. Flies of this genus have been seen flying 

 about on bare sand or in blowouts, hovering especially over hoof- 

 prints or other impressions in the sand. 



Systocchiis vulgaris Loew. August. 



This species w'as not taken because of its scarcity early in the 

 season. Mr. Hart found it quite commonly on flowers. This is the 

 small bee-like form which is parasitic on grasshopper egg-pods. It 

 is quite generally distributed. A very important member of the 

 bunch-grass association, since it is an efficient check upon the num- 

 ber of locusts. 



Proctacanthus brez'ipcnnis Wied. July 6. 



One specimen of this robber-fly was taken at the Devil's Hole, 

 eating a beetle, Strigodcriiia arboricola. The Asilidac are preda- 

 ceous swift-flying forms, dominant among the Dipt era. They are best 

 developed in the open arid associations of the West and Southwest. 

 They are characteristic members of the bunch-grass association. 

 This species has not been recorded from any other Illinois locality. 



Proctacanthus rufus Will. July 8, 12. 



An extremely large and powerful asilid, taken eating Tettigia 

 hieroglyphica on two occasions; once at the Devil's Neck, once at 

 the Devil's Hole. Though characteristically a plains species it ranges 

 east to New Jersey. Hart took P. milhertii Macq. from August 15 

 to 20. This is a western species also, and is reported to prey upon 

 the Rocky Mountain locust. The Asilidac in the Illinois region no 

 doubt prey upon its close relative, Mclanoplus angustipennis, which 

 is the most abundant bunch-grass insect. The range of dates for 

 P. brcvipcnnis is June 6 to July 6; for P. rufus, July 8-12 (it 

 was seen later than this); and for P. milbcrtii, August 15-20. A 

 seasonal relation seems to be clearlv indicated. 



