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UNITED STATES NATIONAL MUSEUM BULLETIN 224 



Legs: The femora are all quite stout, shining, very 

 dark brown but not black. The tibiae are almost as 

 dark as the femora, the tarsi likewise. Claws reddish 

 on the basal half, black apically. Empodium flattened 

 and reddish. Pulvilli long but rather slender and light 

 reddish brown. Pile of the legs shaggy, coarse, long, 

 slightly appressed dorsally, not quite erect ventrally, 

 and everywhere abundant. On the tibiae the pile is 

 somewhat less abundant laterally. Bristles unusually 

 numerous and light reddish brown. Hind femur with 

 5 or G ventrolateral bristles, partly doubled near the 

 apes, with 3 lateral bristles in the middle, 4 dorsolateral 

 and 1 subapical dorsal pair, and 2 apical dorsomedial 

 and 1 apical medial bristle. Hind tibia with 6 dorso- 

 lateral, 6 to 8 dorsomedial, and 3 ventrolateral bristles 

 on the outer half. There is a comparatively long fringe 

 of brownish yellow, erect pile on the ventral surface of 

 the hind tibia. Ventral bristles of the tarsi and a few 

 of the dorsal bristles black. 



Wings: The wings are tinged with light, reddish 

 brown, the costal cell rather distinctly yellowish, the 

 base of the wing broader, the fourth posterior cell with 

 a short stalk and shallow, marginal notch and the anal 

 cell with a conspicuous notch. The wing tends to be 

 somewhat paler in the middle of the post-marginal cell. 

 The first posterior cell is closed and stalked, the third 

 posterior cell is unusually wide on the margin, slightly 

 wider than the fourth. Anal cell closed in the margin, 

 the alula moderately wide, the posterior crossvein al- 

 most wanting, the third vein forks nearly opposite the 

 discal cell. The anterior crossvein enters the discal cell 

 slightly beyond the middle, the thyridium of the fourth 

 vein lies before the base of the discal cell. Marginal 

 cell widely open. Second and third veins curved for- 

 ward into the cost a at the same angle or curve. 



Abdomen : The abdomen is robust, shining black to 

 just beyond the middle of the fourth tergite. The sides 

 of the second to fifth tergites have in the posterior 

 corners triangular bands or patches of yellowish grey 

 pollen. This patch is quite small on the fifth segment, 

 largest on the second and third and on both of these it 

 continues quite narrowly along the middle portion of 

 the membranous, posterior margin. The remainder of 

 the abdomen, the last part of the fourth segment and 

 beyond shining, brownish orange with scattered, golden 

 appressed pile. The terminalia are rather darker, more 

 reddish brown, nearly black on the apical processes. 

 The second tergite is the longest and the tergites 

 slightly decrease in length beyond. The seventh tergite 

 is visible dorsally but the exposed portion is perhaps 

 only a fifth as long as the sixth segment; the terminalia 

 rotate, the epandrium fully cleft to the base, each of the 

 forceps large, relatively short and blunt. Gonopod 

 prominent, the hypandrium bluntly triangular. The 

 pile of the terminalia chiefly yellow with a few black 

 hairs on the hypandrium. Sides of the first 3 tergites 

 with abundant, yet loose, long, coarse, conspicuous 

 hairs, most of them yellow, a few of them black. The 

 black pile is more abundant on the second tergite and 

 becomes shorter towards the middle of the tergite. 



Type. Male, Ghanzi, North Bechuanaland, Monga- 

 latsila, April 24, 1925, collected by J. Maurice. Type 

 in the British Museum (Natural History). 



Genus Oratostylum Ricardo 



Figures 85, 487, 969, 978, 1961, 2050 



Oratostylum Ricardo, Ann. Mag. Nat. Hist., ser. 9, vol. 15, p. 

 260, 1925. Type of genus : Oratostylum lepidum Ricardo, 

 1925, by original designation. 



Medium size, elongate, attenuate flies of rather short 

 pilose and bare, bristly appearance. They are allied to 

 Microstylum Macquart and Daspletis Loew by the pres- 

 ence of bristly pile on the lateral metanotum. From 

 Microstylum it is distinguished by the general swelling 

 of the lower face, which extends to within a short dis- 

 tance of the antenna and there is abrupt ; and from both 

 Microstylum and Daspletis by the quite short proboscis, 

 which is only a little longer than the face, cylindrical 

 and attenuate and considerably narrowed on the outer 

 third ; also separated from both by the absence of the 

 abruptly expanded base on the second posterior cell. 

 Length 15 to 20 mm. 



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

 The face is rather strongly produced but only gently 

 convex and receding below. It is short beneath the an- 

 tenna on the upper fifth of the face and is then abruptly 

 produced, continuing this way on the remainder and 

 lower part. The occiput is conspicuous below, quite 

 prominent and thick due to the marked anterior reces- 

 sion of the eye which begins a little above the middle 

 of the head. The occiput everywhere has dense, fine, 

 brownish white pile, the upper half with bristles; the 

 lower bristles consist of 9 or 10 weak elements; the 

 upper 12 near the vertex are quite stout and slightly 

 curved forward. The proboscis is short, only a little 

 longer than the face ; it is gently swollen towards the 

 base from the dorsal aspect but rather strongly swollen 

 from the apex to the base laterally. The distal third 

 is comparatively slender, and subcylindrical, the middle 

 portion compressed laterally, a dorsal ridge is absent, 

 the upper surface is slightly concave, the proboscis is 

 directed horizontally forward. The apex both above 

 and below bears erect, bristly hairs on the outer fifth; 

 the middle ventral portion has a few, long, fine, stiff 

 hairs. The palpus is three-fourths as long as proboscis, 

 the second segment nearly twice as long as the first and 

 a little more slender. Palpus elongate, slender, cylin- 

 drical and conspicuous ; it reaches as far as the end of 

 the face, clearly consists of two segments ; the first seg- 

 ment is broad, excavated, convex ventrally, unusually 

 elongate, with numerous, long, fine hairs. Second seg- 

 ment cylindrical with a few, fine hairs ventrally and at 

 the apex ; without apical pore. First segment distinctly 

 split and hollowed out and troughlike. 



The antennae are slender and generally similar to 

 those of Microstylum. The third segment is of nearly 

 uniform width and bears a small, more narrow, cylindri- 

 cal, spine-tipped microsegment ; first segment conspic- 



