TAXONOMY OF MUSCOIDEAN FUES — TOWXSEXD 83 



Three postsutural bristles, no acrostichal bristles either before or 

 behind suture. Only one sternopleural bristle (possibly one has 

 been lost anteriorly on both sides). 



Scutellum with a weak apical pair of bristles that are strongly 

 decussate. Also a much longer marginal subapical pair, and a weak 

 marginal pair behind last. 



Abdomen strikingly Ichneumon-like in outline, consisting of five 

 segments- visible from above. Basal segment narrow, but little 

 wider than base of scutellum, narrowed behind. Postbasal or sec- 

 ond segment still narrower on basal portion, the greatest constric- 

 tion being at about anterior three-fourths of the segment where the 

 abdomen is narrower than scutellum. The second segment grad- 

 ually widens posteriorly from the point of its greatest constriction, 

 until on hind border it is twice its anterior width. The third seg- 

 ment widens posteriorly at not quite same angle, the fourth or pre- 

 anal segment narrowing posteriorly about as rapidly as the third 

 segment narrows anteriorly. Anal segment still narrowing pos- 

 teriorly and evenly rounded on apex. The basal and anal segments 

 are about same length, the second segment nearly twice as long. 

 The third and fourth segments are equal and each is a little over 

 twice as long as anal. 



Second, third, and fourth segments with a median marginal pair 

 of macrochsetas quite removed from posterior border of segment, 

 also a lateral marginal one on each side. Anal segment with only 

 an outer pair on each side near hind margin. Second segment with 

 a lateral one in middle on each side. 



Ventral plates not visible, except that the basal plate shows 

 plainly with adjacent ventral membrane rather widely surround- 

 ing it. 



Wings elongate and narrow, reaching about to end of abdomen. 

 No costal spine. Small crossvein nearly opposite end of first vein,, 

 distinctly beyond middle of discal cell. Hind crossvein in middle 

 between apical crossvein and small crossvein, strongly bisinuate.. 

 Apical crossvein still more strongly bisinuate, quite S-shaped. 

 Fourth vein produced beyond apical crossvein in a short stump. 

 Petiole of apical cell half as long as apical crossvein, reaching an- 

 terior wing border well before wing-tip. No veins spined, not even 

 third vein at base. 



Tegulse of moderate size, inner portion subsemicircular in out- 

 line, so transparent (except narrow borders) that the halteres be- 

 neath are almost as clearly seen through them as through glass. 



