458 NORTH A:Mi;RirAX diptera 



392. Posterior tibiae evenly and closely ciliate above with fairly long 



bristles, only one of which may be longer and stronger 420 



Posterior tibiae not evenly ciliate 393 



393. Arista bare or pubescent 395 



Arista plumose 394 



394. Cheeks half as wide as eye-height (128, 131) Zelia Desvoidy 



Cheeks much narrower Minthozelia Townsend 



395. Apical cell ending far before the wing-tip 409 



Apical cell ending at or near the wing-tip 39G 



396. Costal spine not strongly developed, never as long as the width of the 



costal cell and not outstanding, if somewhat long the parafacials 

 are decidedly narrower than the witlth of the third antennal seg- 

 ment 398 



Costal spine longer than the width of the costal cell 397 



397. Facial ridges convex in profile; tliscals present. 



Phrynofrontina Townsend 

 Facials ridges concave below; discals absent (48, 49). 



Spathidexia Townsend 



398. Female abdomen not strongly keeled 399 



Female abdomen strongly keeled, the edges of the tergites spined. 



Jicaltepecia Townsend 



399. First vein bare 400 



First vein with strong bristles on the apical half; antennae arising 



above the midtlle of the eyes Clausicellana Curran 



400. Lower margin of head not strongly oblique on anterior half; posterior 



sublateral present 401 



Lower margin of the head strongly oblique on the anterior half; 

 posterior sublatei'al absent; three pairs of scutellars. 



Pelatachina Meade 



401. Apical abdominal segment horizontal, the genital opening visible from 



posterior view , 402 



Apical abdominal segment vertical, the genital opening wholly ventral. 



Panacemyia Townsend 



402. Male with orbitals (rarely with a single one in the frontal row); 



outer verticals of ? two-thirds as long as the verticals 40fi 



Male without orbitals; outer verticals of ? little more than half as 

 long as verticals 403 



403. Third antennal segment at least three times as long as wide, or not 



unusually large 404 



Third antennal segment very large, long and almost half as wide as its 

 length *Elephantocera Townsend 



404. Palpi not unusually swollen; third vein with two or three basal 



setulae 403 



Palpi greatly swollen; third vein setulose to small crossvein 406 



* Curran, 1930, Bull. Amer. Mus. Nat. Hist., Ixi. p. 96. 



