202 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



are also fewer in some other species. Middle tibia with 

 3 moderately stout, anterodorsal bristles and 2 distal 

 and 2 or 3 more slender, basal bristles. Apex of middle 

 tibia with a stout, spikelike, straight, anterior bristle, 

 or spine. On the anterior tibia there are 2 or 3 short, 

 anterodorsal bristles on the outer third and sometimes 

 near the base there are 1 or 2 long, slender hairs. The 

 posterodorsal row contains 4 or 5 slender bristles, 

 stronger on the outer half. Apex without spine but 

 with several long, stout bristles. Claws slender, sharp, 

 bent at the apex; pulvilli long; empodium slender. 



Wings: The wings are hyaline with weak, diffuse, 

 brown spots on the crossveins and furcations which 

 sometimes may be nearly absent. Marginal cell widely 

 open, all posterior cells and anal cells widely open, 

 third vein branched opposite, before or barely beyond 

 the end of the discal cell. Alula quite narrow ; ambient 

 vein complete, the anterior crossvein enters the discal 

 cell at the distal third or distal fourth of the discal 

 cell. 



Abdomen : The abdomen at the base is as wide as the 

 mesonotum but tapering beyond the first segment. It is 

 comparatively bare, feebly shining black, with polli- 

 nose spots or bands on the base of the segments. The 

 pile is scanty, very fine, setate and suberect but becomes 

 longer and erect on the sides of the tergites, especially 

 the first three tergites. Sides of first tergite with 3 to 

 5 weak bristles and with additional long, stiff hairs. 

 Male9 with seven tergites, the seventh is less than half 

 as long as the sixth or even reduced to a linear trace. 

 Females with eight tergites, the last two each about 

 half as long as the sixth. Male terminalia rotate and 

 comparatively short. The epandrium is cleft to the 

 base with sides apposed or in some species there may 

 be a wide V-shaped notch or sulcus reaching only to 

 the basal third in which is enclosed the dorsal proctiger. 

 Hypandrium quite short, or of moderate length. Gono- 

 pod wide at the base but short and rather strongly nar- 

 rowed and pronglike distally. Females with acantho- 

 phorites and 4 pairs of short spines. 



Distribution : Nearctic : Bachomyia anomalus Wilcox 

 and Martin (1957) ; hannai Wilcox and Martin (1957) ; 

 Umpidipennis Wilcox (1936) ; schJingerl Wilcox and 

 Martin (1957). 



Genus Metapogon Coquillett 



Fiqubes 124, 570, 987, 996 



Metapogon Coquillett, Proc. Ent. Soc. Washington, vol. 6, p. 181, 

 1904. Type of genus : Metapogon gilvipes Coquillett, 1904, 

 by original designation. 



Small flies of dark color, comparatively slender form, 

 pullinose, with short, fine, scanty pile and prominent 

 bristles. They will be recognized by the high, arched, 

 somewhat compressed mesonotum, with conspicuous, 

 long, dorsocentral bristles and prominent acrostical 

 bristles, and the presence of a stump vein from the 

 obtuse base of the second submarginal cell. At least 1 



pair of scutellar bristles is present, the ocellarium with 

 2 or 3 pairs of long, stout bristles, the short, gently con- 

 vex face with numerous bristles below. Protibial apex 

 without spine. Length 8 to 10 mm. 



Head, lateral aspect : The head is of medium length, 

 the face at the antenna is nearly plane with the eye, 

 gradually becoming more prominent below, its apparent 

 length accentuated by the recession of the eye. The 

 occiput is moderately prominent, except at the imme- 

 diate vertex and on all sides it slopes rather strongly 

 away from the eye, becoming most prominent near the 

 outer fourth of the head. The occipital pile below is 

 dense, exceptionally fine and twisted ; stout bristles be- 

 gin at the middle of the head and consist of 10 pairs 

 with an additional row of 4 bristles on each side of the 

 postvertex. The proboscis is short, robust, a little 

 tapered, the apex blunt; the dorsal carina over the mid- 

 dle is high and the apical third below has bristly hair. 

 The palpus is rather large, of two segments; the first 

 is short and excavated, the second is long, cylindrical, 

 attenuate, porate, and without apical pile. The an- 

 tenna is attached a little above the middle of the head, 

 about the same length as the head and slender. The 

 first two segments are short, the first robust, the second 

 beadlike; the first bears 2 to 3 stout, long bristles be- 

 low, the second has only 1 and both with stiff long setae 

 above. Third segment narrow, \y<> times as long as the 

 first two segments combined, a little attenuate at the 

 apex and with two microsegments, the first microseg- 

 ment short, the second microsegment is long with spine 

 at tip and bent downward. 



Head, anterior aspect : The head is a little wider than 

 the thorax, the face wide, at least two-fifths the head 

 width. The face is pubescent with abundant, long, 

 stiff pile on the upper two-thirds and a few weak 

 bristles; below on the receding ventral portion are 

 numerous, long, slender bristles. Subepistomal area 

 large, oblique, plane or slightly convex. Front pol- 

 linose, wide, very slightly divergent with a few stiff 

 hairs on either side. The vertex is moderately exca- 

 vated, the ocellarium is exceptionally large with nearly 

 vertical sides and with 2 to 3 pairs of conspicuous, stout, 

 long bristles and sometimes additional bristly hair on 

 the anterior and posterior parts. 



Thorax: The mesonotum is exceptionally high and 

 strongly arched anteriorly and posteriorly; the middle 

 anterior portion tends to be laterally compressed, the 

 whole pollinose, the sides thinly beset with fine, erect, 

 rather long bristly pile. The mesonotum has a distinct, 

 double row of long, slender, acrostical bristles and a 

 row of still longer, sharp, stout, dorsocentral bristles, 

 all curled backwards ; there are 6 pairs in front of the 

 suture and 5 or 6 pairs behind. The suture is placed 

 unusually far to the rear. Humerus with fine pile. 

 The lateral complement of bristles includes 2 noto- 

 pleural, 1 supraalar, 1 postalar, and 1 stout and 2 very 

 slender pairs of scutellar bristles. Scutellum convex, 

 coarsely pubescent, with scattered fine pile. Metano- 

 tum micropubescent only. Only the metapleuron with 



