SCENOPINID^E. 69 



TABLE OF GENERA. 



1. First posterior cell entire, not intersected by a cross-vein. . . 2 

 "First posterior cell divided by a cross-vein into two cells; first antennal 



joint unusually large." . . . METAPHRAGMA Coquillett. 



2. Head much broader than long. . 3 



" Head not as broad as long, vertical diameter of eyes equaling their 



horizontal diameter; first joint of antennae unusually large and pol- 

 ished". . . . . . . . NEBRITUS Coquillett. 



3. Third joint of antennae short, the first thickened. . TABUDA Walker. 



Third joint of antenna as long or but little shorter than the usually 



slender first joint 4 



4. Face bare or pubescent PSII.OCEPHALA Zctterstedt. 



Face pilose. 4 



5. Fourth posterior cell closed THEREVA Latreille. 



Fourtli posterior cell open. .... DIALINEURA Rondani. 



23. SCENOPINIM:. 



Flies of moderate or small size, black in color and bare. 

 Front not excavated ; face bare, short and broad. Antennae 

 approximated at the base, the first two joints short, the third 

 elongated, simple, without style or arista. Proboscis conceal- 

 ed ; palpi cylindrical, bristly at the tip. Ocelli present. Males 

 usually holoptic. Thorax rather long, moderately convex, 

 though apparently much so from the low position of the head. 

 Scutellum broad and short, without spines or tubercles. Ab- 

 domen flattened, more or less elongated, composed of seven 

 segments. Tegulae small. Empodia wanting. Third longi- 

 tudinal vein of the wing furcate ; basal cells long, the first 

 much longer than the second ; three posterior cells, the first 

 narrowed in, or closed before the margin ; anal cell closed. 



The larvae resemble closely those of the Therevidee. They 

 are very long and slender, having apparently nineteen seg- 

 ments, due to each of the abdominal segments except the last 

 being divided by a strong constriction. The larvae have been 



