FAMILY TACHIXID.E THE TACHIXIDS 461 



437. Apical abdominal segiTient horizontal, the genital opening evident 



from posterior view 438 



Apical abdominal segment vertical at apex, the genital opening- 

 ventral (117, 126) ■Calodexia Wulp 



438. Costal spine not strongly developed; oral margin prominent; wings 



not brown with pale spots 439 



Costal spine long; oral margin and vibrissal angles scarcely raised; 

 wings brown with hyaline spots Jamacaria Curran 



439. Largely yellowish species 441 



Wholly black species; wings partly brown 440 



440. First vein bare; third with a single basal bristle (Plectops?). 



Nephopteropsis Townsend 

 First vein setulose Slossonaemyia Townsend 



441. Third antennal segment narrower than the second or the fifth vein 



bare 442 



Third antennal segment wider than the second, the fifth vein setulose. 



Trichotopteryx Townsend 



442. Head at most one and one-half times as high as long 443 



Head almost twice as high as long Xanthodexia Wulp 



443. Palpi variable, sometimes shortened, usually curved, never broad and 



flattened 444 



Palpi long, broad antl flattened on the apical half or more, never 

 curved (112) Genea Rondani 



444. At most two presutural acrostical or dorsocentral bristles 44G 



Three presutural acrostical and dorsocentral bristles 445 



445. Abdomen with discals (36) Binghamimyia Townsend 



Abdomen without discals Pyrrhosia Rondani 



446. Abdomen cylindrical or wider than deep apically 447 



Abdomen laterally compressed on the apical half; small, slender 



species Xanthomelanopsis Townsend 



447. First abdominal segment with marginals 448 



First abdominal segment without marginals (93) Fischeria Desvoidy 



448. Three sternopleurals Solieria Desvoidy 



Two sternopleurals Opsoleskia Townsend 



449. Arista bare or pubescent 456 



Arista plumose, very long pubescent or short pectinate 450 



450. Arista plumose or pectinate 451 



Arista long pubescent; antenna arising at the lowest third of the 



eyes; clypeal region long Eumegaparea Townsend 



451. Abdomen without discals 452 



Abdomen with discals ( 132 ) Chaetona Wulp 



452. No strong presutural acrosticals Phyllophilopsis Townsend 



At least one pair of strong presvitural acrosticals 453 



453. Ocellars weak or absent 454 



Ocellars well developed Pseudodexia Brauer & Bergenstamm 



* Curran, 1934, Amer. Mus. Novit. No. 685, pp. 1-21. 



