489 



and tarsi brown. Wings slightly brownish owing to the dense cov- 

 ering of hairs, veins brown. Halteres yellow or pale brown. 



Antennae about one and a half times as long as head and thorax 

 together, the plumes very long. Thorax projecting very much an- 

 teriorly; pronotum linear, not extending to upper margin of meso- 

 notum. Hypopygium as in Figure 6, Plate XXXVI. Legs, includ- 

 ing fore tarsi, with moderately long hairs; basal joint of fore tarsi 

 nearly one half longer than fore tibiae (63:44). Third vein ending 

 well in front of apex of wing ; cubitus forking below base of fourth. 



Female. — Differs from the male in having the ground color of 

 the thorax yellowish and the legs yellowish brown. 



Except in the sexual characters and in the absence of long hairs 

 on fore tarsi it agrees structurally with the male. 



Length, 3.5-4 mm. 



This species very probably occurs in Illinois. The only examples 

 I have are one larva from Montana (C. C. Adams), and a male and 

 a female sent me by Professor Johannsen from Ithaca, N. Y. 



3. Tanytarsus neoflavellus, n. sp. 



Male. — Yellow, slightly shining. Flagellum of antennje slightly 

 brownish. Abdomen greenish yellow. Legs entirely pale yellow, 

 only the apical comb of the hind tibiae black. Wings clear, veins en- 

 tirely yellow. Halteres yellow. 



Antennae about one and a half times as long as head and thorax 

 together. Thorax much swollen anteriorly; pronotum of moderate 

 width, not continued to upper margin of mesonotum. Hypopygium 

 similar in general appearance to that of viridivcntris (PI. XXXVI, 

 Fig. 8), the superior process being like that of Figure i of same 

 plate, and the inferior one as in Figure 8, h, Plate XL. 



Fore tarsi exceptionally long, not very slender, and without long 

 hairs; lengths of fore tibiae and fore tarsal joints as follows: 24, 

 63, 25, 22, 19, 8; mid and hind legs with moderately long hairs. 

 Wings distinctly hairy; third vein clearly ending before apex; cross 

 vein appreciably before wing-middle and fork of cubitus. 



Female:- — Yellow, including the abdomen. 



Agrees with the male except in sexual characters and in having 

 the cross vein nearer to base of wing. 



Length, 2.5-3.25 mm. 



Type locality, Dubois, 111., April 24-25, 1914, at light and by 

 sweeping vegetation on bank of creek. 

 Early stages unknown. 



