256 Illinois State Laboratory of Natural History. 



Scutellum black, at least at base, its spines rudiment- 

 avy, very minute and scarcely visible, or entirely 

 wanting, face strongly protuberant. 

 Thorax, face, and scutellum, except sometimes nar- 

 row apical margin of latter, black; scutellar spines 

 minute; antennae dark rufous, base and apex 

 black, c?. snowi n.s.* 



Four angles of thorax, scutellum pxcept at base, and 

 sides of thoiax beneath broadly light greenish; 

 scutellar spines entirely wanting; antennae black. 



hieroglyphica^ 

 O. intermedia Wied. 



The adult was taken in Champaign and Lake counties 

 May 23 to June 19 in low ground or near water. 



O. jpiibescens Day. 

 Adult, Lake county, near Sand Lake, June 15. 



O. plebeja Loew. 



The imago is very common in Illinois, usually in low 

 grounds, upon flowers. We have it from near the Mis- 

 sissippi River in Carroll county, also from Lake and 

 Bureau counties, both northern ; from McLean and 

 Champaign counties; and from Wabash county in south- 

 eastern Illinois. It has been taken at frequent intervals 

 from May 28 to August 2, at which latter date several 

 were found. 



0. pilimana Loew. 



Also common as an adult, apparently somewhat later 

 than pleheja. The earliest date is July 15, after which 

 it frequently occurred and was still abundant at the last 

 date recorded for the species— August 2. From Carroll, 

 Bureau, LaSalle, De Kalb, and Champaign counties. 

 0. cincta Oliv. {extremis Day). [Fig. 58, 59.] 



This species was in all its stages the most abundant 

 aquatic stratiomyiid at Havana, though the imago has 

 rarely occurred in our general collections. 



♦ Named after Mr. W. A. Snow. The characters given will suffice without further 

 description. 



