56 INSECUTOR INSCITL^ MENSTRUUS 



This form will probably best be treated as subgenus B of 

 Bpidexia. 



Oxynops Townsend. 



Jn. N. Y. Ent. Soc. XX, 110-111 (June, 1912). 



Genotype, Hypostena nitens Coquillett, 1897, Rev. Tach. 63 

 (Syn. Oxynops serratus Townsend, 1912, 1. c, holotype 19468, 

 U. S. Nat. Mus., female, TD1282). 



Small metallic flies. May be distinguished by the following 

 characters : Female. — Vertex rather less than one-fourth head- 

 width, the front and face very slightly widening therefrom, 

 face below over one-third head-width. Eyes very faintly 

 short-hairy, Facialia strongly ciliate. Parafacials very nar- 

 row, almost linear below. Cheeks narrow, the eyes descending 

 nearly to vibrissse. Facial depression sunken ; the epistoma 

 cut off, notched in middle. Frontalia wider than one para- 

 frontal. Antennae reaching oral margin, second joint short. 

 Arista thickened on less than basal half, the basal joints short. 

 Proboscis short and fleshy, palpi enlarged at tip. Two pro- 

 clinate and two reclinate fronto-orbitals, outer vertical de- 

 veloped but short, proclinate ocellars present, frontals reach- 

 ing to base of third antennal joint. Vibrissse on oral margin. 

 Erect median marginal bristles on first abdominal segment, 

 median marginal and discal on second and third segments, 

 weaker marginal and discal on anal segment. Claws short. 

 Larvipositor elongate, sheathed within a subconical base formed 

 of broad upper and lower plates ; no piercer. Apical cell open, 

 ending almost in wing-tip; hind crossvein nearly in middle; 

 third vein spined halfway or more to small crossvein, latter 

 at end of auxiliary vein. 



Male. — Differs from female as follows: Third antennal joint 

 enlarged, rounded and bulged apically. No proclinate fronto- 

 orbitals. No median discal macrochsetas on third abdominal 

 segment, the marginal row of anal segment strong. Hypopy- 

 gial forceps elongate and slender. 



