186 



of this bee-fly was taken Aug. 23 (No. 146). Graenicher ('10, p. 93) 

 has Hsted a variety of plants visited by this fly. 



The habits of this species appear not to be known, but the larvae 

 of an allied species, S. areas O. S., preys upon the eggs of grasshoppers 

 (Riley, Second Rep. U. S. Ent. Comm., pp. 262-268. 1880). Shel- 

 ford ('13c) has found that Spogostyhnn analc Say is a parasite on the 

 larva of Cicindda. A related fly, SparnopoUiis fulvus, is parasitic 

 on the grubs of Lachnosterna (Forbes, '08, p. 161). Holmes ('13) 

 has shown the relation of light to the hovering flight of Bomhylius. 



Mydaid^e 



Mydas clavatus Drury. Giant fly. 



A single specimen of this giant fly was taken on flowers of the 

 swamp milkweed, Asclepias incarnata (Station l,d), Aug. 9 (No. 

 12). I have taken this species at Chicago during July, and at Bloom- 

 ington, 111., on June 29. 



Harris (Insects Injurious to Vegetation, p. 607. 1869) describes 

 briefly the larva and pupa; and Washburn (Tenth Ann. Rep. State 

 Ent. Minn., PI. II, fig. 15. 1905) gives a colored figure of the species. 



The larvse of this family live in decaying wood and prey upon 

 insects, and the adults are also predaceous (Hubbard '85, p. 175). 



Howard (Insect Book, p. 136) states that the larva of Mydas 

 fuh'ipcs Walsh "lives in decaying sycamore trees and is probably 

 predatory on other insects living in such locations." He also states 

 that the adults are predaceous. 



ASILID^E 



Dcromyia sp. 



This robber-fly was taken on the Loxa prairie (Sta. II) Aug. 13 

 (No. 51). 



The larvse of some members of this family feed upon rhubarb 

 roots (Harris, Ins. Inj. to Vegetation, p. 605. 1869), and others, as 

 Brax bastardi, are known to prey upon the eggs of grasshoppers 

 (Riley, First Rep. U. S. Ent. Comm., pp. 303-304, 317. 1878). 

 Adults of several species of robber-flies feed upon grasshoppers; 

 others kill bees (Riley, Sec. Rep. Ins. Mo., pp. 121-124. 1870). 



Promachus vcrtcbratus Sav. Vertebrated Robber-flv. (PI. XLVI, 

 fig- 6.) 

 This is an alumdant fly upon the prairie. A specimen was taken 

 on the Loxa prairie (Sta. II) Aug. 13 (No. 56) ; and on the prairie 

 east of Charleston (Sta. Ill, b) Aug. 15 (No. 62). Here a robber- 

 fly was seen with a cabbage butterfly, Pontia rapcu (No. 61) ; since the 



