AKT 11. NOTES ON NEAECTIC BIBIONID FLIES — McATEE. 23. 



DILOPHUS SEROTINUS Loew. 



Dilophus serotinus Loew (H.), Dipt. Amer. sept, indig., Cent. 1, No. 15, 

 1861; Compl. Work, pp. 9-10 [Illinois]. 



Male. — Entirely shining black, shorter hair of eyes and longer 

 hair of hind part of abdomen, distal parts of tibiae and of the tarsi 

 black, of remainder of body pale ; halteres black and the stalk pale ; 

 wings and veins dusky to blackish, darkest costally; stigma large; 

 genital segment cleft about half its length; superior plate half as 

 long as wide, its hind margin somewhat rounded and shallowly but 

 distinctly emarginate in middle. 



Female. — Head black; thorax yellow to rufous, humeri, pleura, 

 combs, and scutellum more or less touched with black; abdomen 

 velvety brown to black; genitalia tipped with yellow; coxae (except 

 hind ones sometimes in part) and femora except ends yellow to 

 rufous; trochanters, tibiae and tarsi brown to black; hair of head, 

 body and legs to and including femora pale, of tibiae and tarsi dark ; 

 halteres and wings as in male. 



Length of wing, 4.5-8.5 mm. 



Specimens examined are from Kansas, Missouri, Illinois, Mary- 

 land, Virginia, and Mississippi. 



DILOPHUS SPINIPES Say. 



D. [ilophus'[ spinipes Say (Thomas), Des. Dipt. U. S., Journ. Acad. Nat. 



Scl. Phila, vol. 3, 1823, pp. 79-80; Compl. Writings, vol. 2, 1859, p. 71 



[Missouri]. 

 D. [ilophtis] thomcicus Say (Thomas), Des. Dipt. U. S., Journ. Acad. Nat. 



Sci. Phila., vol. 3, 1823, p. 80; Compl. Writings, vol. 2, 1859, pp. 71-72 



[Pennsylvania, Maryland]. 

 Dilophus dimidiatus Loew (H.), Dipt. Amer. Sept. indig., Cent. 8, No. 3, 



1869; Compl. Work, vol. 2, p. 118 [New York]. 



There is considerable variation in size and color in this species, 

 sufficient in my opinion to cover the three described forms above 

 cited. This is the only nearctic species having three series of spines 

 on the front tibia. 



3Iale. — Rostrum long, extended proboscis longer than antennae; 

 lower part of compound eyes black, upper reddish, thorax in general 

 rufous, but prothorax, the toothed ridges, middle of pleura and 

 scutellum black; abdomen velvety black; genital segment cleft 

 about half its length, superior plate about three times as wide as 

 long, hind margin rounded angulate; front and mid coxae and 

 femora chiefly rufous; remainder of legs black; hair of head, body 

 and legs black; halteres dusky, wings and veins dusky, darker 

 costally. 



This, the only male at hand, is of the thoracicus type, but it is 

 believed that variations in this sex parallels that of females, as 



