INSECTA. 
643 
1. Last portion of 4th longitudinal vein pnrnllcl, or noa»ly so, to 
8rd longitudinal vein 3. Gymnopternus. 
2. Last portion of 4th longitudinal vein distinctly convergent to- 
wards 3rd longitudinal vein. 
a. End of 4tli longitudinal vein abruptly or steeply deflected 
anteriorly. 
a. Arista with the usual pubescence ; end of 4th longitudinal 
vein curved 4. Paraclius, g. n. 
h. Arista shortly plumose; end of 4th longitudinal vein 
straight 6. Pelastoneurus. . 
b. End of 4th longitudinal vein gradually deflected anteriorly. 
a. Face reaching down to inferior corner of eye. 
G. Taciiytrechus. 
h. Face not reaching inferior corner of eye. 
— Proboscis and palpi very much prolonged. 
7. Orthochile. 
= Proboscis and palpi not prolonged. 
** Scutellum hairy 8. Sybistroma. 
ft Scutellum not hairy. 
aa. Hypopygium sessile . . 9. HercoStomus. 
/3/3. Hypopygium pedunculated. 
Second antennal joint of usual shape. 
10. IIypophyllus. 
Second antennal joint rudimentary. 
11. Haltericerus. 
B. Hypopygium more or less imbedded. 
* Abdomen of S laterally compressed .... 13. Anepsius. 
t Abdomen of ^ not compressed. 
a. Second antennal joint of the usual shape. 
14. Argyra. 
/3. Second antennal joint with a thumb-like projection over the in- 
side of the third 16. Syntormon. 
II. First antennal joint glabrous above. 
A. Third antennal joint (at least in (5') prolonged, pointed, with an 
apical arista. 
* Second antennal joint with a thumb-like projection over the inner 
side of the third 16. Synarthrus. 
t Second antennal joint simple. 
a. Posterior transverse vein approximated to margin of wing; palpi 
hanging down 22. Aphrosylus. 
/3. Posterior transverse vein distant from margin ; palpi incumbent. 
1. Hypopygium pedunculated, free .... 17. Systenus. 
2. Hypopygium sessile, imbedded. 
a. Abdomen in with 6 segments. . 21. Smiliotus ( = 
chcerium, Hal.). 
b. Abdomen in S with 6 segments. 
