317 



Length: female, 4.5 mm. ; male, 3-3.5 mm. 



Type locality, White Heath, 111., on bank of Sangamon River, May 

 9, 16, and 30, 1915 (J. R. Malloch). 



The female of this species will run down to section 8 in my key to 

 the species of Prohezzia in the paper previously mentioned, and may 

 be separated from alhiventris, the only other described species with 

 black halteres. by the infuscated abdomen, differentlv colored lees, 

 and infuscated wmgs. The male will run down to section 14, and is 

 readily separated from the species included therein by the dark hal- 

 teres. The male of alhiventris is not known, but must closely resemble 

 that of infuscata. 



The early stages and the habits of the imago are unknown. 



TANYPIN^ 



Tanypus carnkus Fabricius 



The only Illinois records I had of this species when I wrote my 

 paper was that of a larva from the Illinois River. On June 18, 191 5, 

 I took a male imago on a window in the basement of 'the Natural His- 

 tory Building of the University of Illinois, at Urbana, which agrees 

 with the description of the species in almost all respects, the only de- 

 parture being in the color of the abdomen, which has a broad dark 

 brown anterior band on all segments but the fourth, the latter being 

 entirely whitish yellow. Single examples of the female were taken on 

 July 21 and August 13. I have no doubt as to the identity of the 

 species. 



Descriptions of Males of CERAToroGONiN^ 



PREVIOUSLY UNKNOWN 

 JOHANNSENOMYIA ARGENTATA LoCW 



Male. — Glossy black. Head black, basal portion of flagellum of 

 antennae and their plumes fuscous, the latter with a whitish luster 

 when viewed from certain angles ; mouth parts brownish. Mesonotum 

 without distinct pruinescence. Abdomen in some specimens with a 

 faint hoary pruinescence when viewed from behind. Legs yellowish, 

 mid and hind coxae, apices of fore femora narrowly, of mid femora 

 broadly, and almost the whole of hind femora, blackened, as also are 

 the bases and apices of fore and mid tibia?, the entire hind tibiae, the 

 apices of the basal four tarsal joints, and the whole of the fifth joint 

 of all legs. Wings slightly grayish, radius and basal portion of upper 

 fork of media blacker than other veins. Halteres black. 



