/' 7/.\7;r.i/o.v FLIES— Asinn:. i />. 33 



length of the second; Hrnt joint of the liagelknn lunger than the 



«'(•( )n(l ( 1 7<) ) Thcdis Fijnster. 



Paraiwiilal fnrrows not uniting at the niiddk' of the luessonotuni; 

 areolet regularly formed: first al)wissca of radinss not half the 

 length of the second; first joint of tlagelluin shorter than the 



sect )nd ( 1 77 ) Peinon Fiirster. 



i). .Metathorax with the petiolar area hounded hy a prominent ridge ahove, the 



• middle lateral area also prominent (178) Trlmcra Forster. 



Metathorax with the petiolar area not hounded l>y a prominent ridge ahove. 



Metanotnm incompletely areolated 14 



IMetanotuni completely areolated. 



Face not clothed with long glittering white hairs; mesoiiotum with 



the parapsidal fnrrows incomplete or wanting 10 



Face clothed with long glittering white hairs; mesonotum with the 

 parapsidal furrows complete. 



Face very nuich narrowed (179) hchnurynpx Forster. 



Face hroad (180) Steganop^ Forster. 



10. ^liddle lateral areas very strongly toothed (181) hcliyrach Foster. 



Middle lateral areas not strongly toothed. 



Clypeus distinctly separated; anal valves in male small; mandil)les not 

 emarginate at the middle 11 



Clypeus not separated, wholly hent downward, the anterior margin 

 stjnarely truncate; anal valves in male very large, prominent; 

 mandil)les very small, emarginate medially. 



(182) AMomai<pi^ Forster. 



11 . Petiolar area not confluent with the areola 12 



Petiolar area confluent with the areola and extending nearly to the hast' of the 



metanotnm; antenme 18-jointed, toward apex clavate. 



(183) 3f/m_>/;/r.i.' Forster. 



12. First joint of flagellum fully as long or longer than the second 13 



First joint of fiagellum a little shorter than the second (184) Lydhki Forster. 



i;;. ^Middle vein in hind wings toward the hase obliterated and only visible Iw a 



hyaline line ( 185) Ddi'tora Forster. 



^liddle vein in hind wings distinct, not obliterated at base. 



Metauotum with 5 areas; spiracles of the first abdominal segment very 



prominent (186) Aclmtus Forster. 



Metanotnm with 3 areas; spiracles of the first abdominal segment not at all 

 prominent (187) Opisthostenus Forster. 



14. Metanotnm irltJtout areas at base; wings very narrow. (188) Asthenoptera Forster. 

 ^Metanotnm ivlfh areas at base; wings broad (189) Stygera Forster. 



15. ;\Ietathoracic ridge not interrupted at the middle 16 



]Metathoracic ridge interrujited at the middle. 



First abominal segment short, broad, and strong ..(190) Diaghi/tld Forster. 



16. Eyes distinctly hairy (191 ) Ihihromma Forster. 



Eyes not hairy. 



Ocelli touching the eyes (192) Plet^iomma PTirster. 



Ocelli not touching the eyes. 



Clypeus bare, or nearly, irtlhovt long hairs 1 < 



Clypeus with long hairs, almost forming a fascicle. 



(193) Batlnjthrlr FiirstiM". 



17. First joint of the flagellnm somewhat shorter than the second 18 



First joint of the fiagellum as long as or longer than the second 19 



IS. Third joint of the fiagellum as well as the second joint somewhat longer than 

 thefirst; clypeus anteriorly at the middle impressed and broadly, 



although slightly, emarginate (194) Alg'imt Forster. 



Proc. N. M. vol. xxiii -3 



