186 



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

 has listed 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 Spogostylum anale Say is a parasite on the 

 larva of Cicindela. A related fly, Sparnopolius 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 Bombylius. 



M.YDAIDJE 



Mydas clavatus Drury. Giant fly. 



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

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

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

 ington. III., 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 larvae 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 

 fuhipes 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. 



Deromyia sp. 



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

 (No. 51). 



The larvae of some members of this family feed upon rhubarb 

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

 Brax hastardi, 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 vertebratus Say. Vertebrated Robber-fly. (PI. XLVI, 

 fig. 6.) 



This is an abundant 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 rapce (No. 61 ) ; since the 



