MAY FLIES AND IMIDGRS OF NEW YORK 89 



Imagines 



Note. — In connting the autemial joints the large basal joint is included, 

 but not the hiddon first joint. 



a Wings absent or rudimentary 



?) Wings reduced to mere vestiges, legs short and not slender, antenna 

 with seA'en joints, mouth parts rudimentary, pi. 36, fig.l3, female 



14. C 1 u n i o 



6& Rudimentary wings reaching at least to the end of the first abdominal 



segment 



c Halteres wanting, wings in the form of a flattened racket, tarsal 



claws with a little subapical tooth. Palpi four-jointed ; antenna 



five ( ?) jointed 10. B e 1 g i c a 



cc Halteres distinct 



d Palpi fom'-jointed ; antenna of the female four-jointed, of the male 



six-jointed, pi. .35, figs. 16, 21, 22. 11. E r e t m o p t e r a 



(hi Palpi two-jointed ; antenna of the female six-jointed 



e Second joint of antenna like those following, monilliform, pi. 37, 



figs. 5, 6, 7 12. H a 1 i r y t u s 



ee Second joint longer than those following ; male antenna also 

 with six joints, pi. 35, figs. 4 to 9. ..13. P s a m a t h i o m y i a 

 a a Wings present 



b The M-Cu crossvein present (i. e., cell M closed by a vein), pi. 37, fig.24 

 c Antenna with twelve or more joints 



(/ Antenna with fourteen joints usually plumose ; fourth tarsal joint 

 usually shorter than the fifth ; wing bare, pi. 30, fig.l3, male 



35. D i a m e s a 

 (1(1 Not as above 



c Antennae with fifteen joints both in male and female ; plumose 

 in the former ; the vein M simple, pi. 27, figs. 1 to 15 



{Ch'oup T a n y p u s) 

 f Wing bare 



g Fork of the cubitus petiolate 15. P r o c 1 a d i u s 



gg Fork of cubitus proximad of crossvein 



16. A n a t p y n i a n. gen. 

 ff Wing pubescent 



g Fork of cubitus proximad of crossvein 



li Antennae of male and female each with fifteen joints, R, 



and R3 distinct 17. A b 1 a b e s m y i a n. gen. 



lih Antennae of female with to-elve joints, the male with fif- 

 teen joints, R3 indistinct (Australian genus) 



_ 18. I s o p 1 a s t u s 



gg Fork of cubitus petiolate 19. T a n y p u s 



ee Antennae with twelve or fourteen joints ; wings hairy ; cubitus 

 not forked ; anterior crossvein long and very oblique, pi. 37, 



fig.l6 20. P e n t a n u r a 



cc Antennae with less than ten joints 



d Crossvein near basal third of wing, pi. 37, fig.ll. Antennae about 

 eight-jointed (Chile) 21. Podonomus 



