MAY FLIES AND .AlllKiKS OF XKW VOKK IJl 



dd Yclluwisli or Kveenish species 



c Legs pale; tibiae with black tips; thorax and abdomen yellow; 



length 4 mm T. fascipennis 



ee Some or all femora partly black ; metanotum with brown vittae 

 or spots ; length about 4 mm. 

 f " Metanotum marked with a transverse pair of triangular 



brown spots" 'S- taeniapeunis 



/■/ " jNIetanotum marked with a pair of brown spots which 

 approach each other posteriorly." (This may he a synonym 

 of the taeniapeunis above) . .9. p u 1 ch r i p e n n i s 

 aa AYiugs unmarked, excepting sometimes with darkened crossvein 



1) Dorsum of thorax and abdomen black. The former may have indis- 

 tinct stripes and the latter may have paler incisures 

 c Legs black or fuscous 

 d Thorax shining black 



e Halteres white; wings white, immaculate; male; length 



2.75 mm 10. b r u n n i p e s 



ee Halteres with brown knob ; wings hyaline, very slightly smoky, 

 with anterior veins and crossvein brown; fore metatarsus 

 nearly twice as long as its tibia ; length 3.5 mm. 



11. b r u n n e i p e n n i s n. sp. 

 dd Thorax grayish, with black stripes ; abdomen black 



e xVbdomeu uniformly dark brown or black ; halteres white with 



end of knob brown 12. c a 1 i g i n o s u s n. sp. 



ee Abdomen with whitish incisures or margins 



f. Fore metatarsus % longer than its tibia ; halteres dark in the 

 male, paler in the female; anterior tarsi of the male with 



long hairs 13. n i v e i p e n n i s 



ff Fore metatarsus Vi longer than its tibia 



Anterior tarsi of the male long-haired ; abdominal segments 

 with narrow white posterior margins; wings hyaline with 



black crossvein (Greenland) 14. h y p e r b o r e u s 



.(/(/ Anterior tarsi of the male short-haired; abdominal seg- 

 ments with cinereous margins ; wings slightly cinereous 



15. s t a e g e r i 



cc Legs more or less pale 



d Halteres with gray or black knobs 



e Femur black with yellow apical ring ; tibia black and yellow ; 



wings with black crossvein 16. f 1 a v i c i n g u 1 a 



ee Legs not so marked 



/ Mesonotum and scutellum shining black 



11. b r u n n e i p e n u i s n. sp. 

 ff Mesonotum pruinose, scutellum yellowish ; length 2.3 mm. 



17. h a 1 t e r a 1 i s 



dd Halteres with pale knobs 



c Basal joint or joints of abdouien yellow 



f First and second abdominal segments yellow ; male 



18. n i t i d e 1 1 u s 

 ff First segment only yellow 19. f a 1 1 a x n. sp. 



