Entomology of the Illinois River. 273 



■dull without. The color and texture distinguish it from 

 others I have seen. 



The imago is rather small, 9-10 mm. in length, some- 

 what shining, faintly purplish black, a short inconspicu- 

 ous blackish pilosity ; the wiugs quite blackish, with 

 violaceous iridescence; the pronotum subangulate behind, 

 the propodeum smoothly rounded and shining; second 

 cubital elongate-quadrate, length on radial and cubital 

 veins about equal, third cubital narrowed about one 

 third towards the marginal cell; last abdominal very 

 opaque, with close-set moderately long black setae. 



Family BEMBECIDiE. 



Bemhex sjpinolce Lep. 



This well-known and common sand-wasp was often 

 noted along the sandy east shore of Quiver Lake, and 

 often several at once were hovering about our boat 

 while we were at work at Station A, in the middle of 

 the shallow but broad expanse of water at the head of 

 this lake. Since it is the habit of sand-wasps to provision 

 their nests with Diptera — including among these some 

 which breed in water— they must considerably affect the 

 numbers of such species. 



—18 



