465 



of dimorphus and is altogether lacking in several important details, 

 I do not consider that his species described from "St. Martins Falls, 

 Albany River, Hudson's Bay," can possibly be the same as the Illi- 

 nois species. 



41. Chiroxomus abortivus, n. sp. 



Male. — Pale green, slightly shining. Head yellowish; flagellum 

 of antennae fuscous, yellowish basally; antennal plumes yellowish 

 brown; palpi yellow. Mesonotum with reddish yellow vittse; pleu- 

 r?e mostly suffused with yellowish red; postnotum reddish. Abdo- 

 men without distinct dark marks. Legs greenish yellow; apices of 

 tibiae narrowly blackened; apices of basal two joints of fore tarsi 

 and whole of apical three blackened ; mid and hind tarsi blackened 

 from near apex of third joint to tips. Wings clear, veins pale yel- 

 low, cross vein not infuscated. Halteres greenish yellow. 



Frontal tubercles indistinguishable. Hypopygium as in Figure 9, 

 Plate XXXIV. Fore tarsi without long hairs, basal joint more than 

 a third longer than fore tibiae (50:35) ; mid and hind legs with long 

 hairs. Third vein ending at about the same distance in front of apex 

 of wing as fourth does behind same; cubitus forking very slightly 

 beyond cross vein. 



female. — Differs from the male in having the antennae generally 

 yellow except the last joint, which is fuscous, and in the usual sex- 

 ual characters. 



Length, 4-5 mm. 



Type locality, Urbana, 111., September 5, at light; paratypes from 

 Havana, 111., April 28, on bank of the Illinois River, — all taken by 

 Mr. Hart and the writer in 1914. A female specimen was taken at 

 South Haven, Mich., July 15, 1914, at light, by Mr. Hart. This 

 specimen is rather larger than the females from the other localities 

 mentioned, and has the apices of the fore tibiae less conspicuously 

 blackened, but is obviously the same species. Specimens that agree 

 with the type have also been seen by me from Mendota Lake, Wis., 

 June 8, 1912 (A. C. Burrill). 



42. Chiroxomus fuscivkxtris, n. sp. 



Male. — Reddish yellow, slightly shining. Head yellow, flagel- 

 lum of antennae, except the extreme base, and plumes pale fuscous; 

 palpi reddish yellow. Mesonotum with rather indistinct reddish vit- 

 tae; postnotum brown. Abdomen fuscous, anterior lateral angles 

 of segments yellow. Legs pale yellow, apical tarsal joint brownish. 

 Wings clear, veins yellow, cross vein not infuscated. Halteres yellow. 



