367 



— Smaller species, 2-3 mm., or if over 3 mm. then pale yellow in 



color 3 



3. Large yellow species, 3.5-4.5 mm. ; female without dark marks, the 



male with brown bands on the anterior half of the abdominal seg- 

 ments 2. melanops. 



— Smaller species, 2-3 mm. in length 4 



4. Cross vein of wings infuscated; fore tarsus with basal joint four 



fifths as long as fore tibia 3. decoloratus* . 



— Cross vein not infuscated 5 



5. Male with fore tarsus bearded, the abdomen with pale spots on the 



sides of the segments of the basal half 4. inconspicuus. 



— Male with the fore tarsus inconspicuously haired, segments of abdo- 



men with pale posterior margins 6 



6. The pale margins to segments 2, 4, and 6 very broad. .5. pilosellus. 



— All abdominal segments with pale margins of same width 



6. marginelliis. 



7. Tibiae with 3 brown bands, one near base, one slightly beyond mid- 



dle, and one at apex 8 



— Tibiffi without any brown bands at middle 9 



8. Second brown band on tibiae very distinctly beyond middle, the 



subbasal yellow band distinctly broader than the subapical one 

 7. monilis. 



— Second brown band on tibise near the middle, the 2 whitish bands 



subequal in width, or the subbasal one the narrower 



8. illinoensis. 



9. Wings with distinct spots, not banded 9. venustus. 



— Wings with distinct fascise 10 



10. Legs uniform yellow, only a short black comb at apices of tibiae .... 



10. carneiis. 



— Legs with at least brown preapical band on the femora 11 



11. Numerous clear rounded spots in the preapical fascia of the wing; 



apices of femora and bases of tibige with brown bands. .11. dyari. 



— Preapical fascia irregular, but without any clear rounded spots; 



only the femora with a brown band 12. jolinsoni. 



I, Tanypus hirtipennis Loew 



Tanypus hii-tipennis Loew, Berl. Ent. Zeitschr., 1866, p. 5. 



Male. — Brownish black. Head yellowish; antennae and antennal 

 plumes brown, the second joint almost black; palpi brown. Meso- 

 notum densely gray pollinose, a small subtriangular area behind hu- 

 meri blacker than the rest of disc, each side of the divided central 



*Fastuostis Johannsen is evidently very closely related to this species, but the 

 length of the fore metatarsus is given as .6 the length of the fore tibia. The cross 

 vein is said to be "especially distinct," which separates it from pilosellus and incon- 

 spicuus. 



