LiPHRIINAB 



ROBBER FLIES OF THE WORLD 



377 



sternopleuron. Pile minute, curled, appressed, and 

 pale yellow. Pollen or rather coarse, appressed micro- 

 pubescence is silvery white or grey ; it is limited to a 

 very narrow linear band between the notopleuron and 

 the mesopleuron, and upon the curved, arching depres- 

 sion marking off the posterior mesopleuron and the 

 upper sternopleuron, and which is continued also pos- 

 teriorly on the lower, not depressed sternopleuron. 

 There is similar silvery pubescence on almost the whole 

 propleuron, the hypopleuron, more faintly on the 

 metapleuron, and more densely on all coxae. Propleu- 

 ron with some scattered, stiff, white hairs, appressed 

 backward. Pronotal collar with 9 pairs of spikelike, 

 stout, sharp, yellow bristles. Metanotal callosity with 

 short, yellow bristles and pile. Halteres pale brownish 

 yellow, the base narrowly reddish. Prosternum fused 

 laterally. Notopleuron, supraalar and postalar cal- 

 losity with a single short, yellow bristle. Scutellar 

 margin with a pair of widely separated, still shorter 

 yellow bristles. 



Legs: The anterior four legs including the apices 

 of their coxae, except the last tarsal segment, pale, 

 translucent, brownish yellow. Ventrally on these fe- 

 mora near the base and ventrally over the middle of 

 these four tibiae is an obscure, brownish smudge. Last 

 section of the tarsus, except at the base, is blackish. 

 Hind femur black or nearly black, except on the basal 

 fourth and the extreme apex; these pale yellow or 

 brown and diffusely demarcated. Also the compara- 

 tively robust hind tibia is brownish black except on 

 the basal third, which is pale yellow and not sharply 

 marked off. Hind tarsus brownish yellow ; the last seg- 

 ment, except the base, black. Claws slender, black, 

 brownish yellow at the base. Pulvilli well developed. 

 Pile of the legs very pale yellow to whitish. Ventral 

 surface of the hind femur medially and of the hind 

 tibia have a moderately dense, erect fringe of pale 

 pile. On the tibia it continues erect to the apex. Hind 

 basitarsus is comparatively large and thick, the sec- 

 ond and third segments also somewhat swollen. The 

 anterior basitarsus also rather thicker than the succeed- 

 ing segments. Bristles few and weak and only mod- 

 erately more prominent on the tibia, perhaps most 

 conspicuous on the anterior tarsal segments and all 

 the bristles pale, brownish or reddish yellow. Posterior 

 trochanter at apex anteriorly with a dark, bi-own spot. 



Whigs: The wings are distinctly tinged with pale 

 brown but somewhat lighter at apex and post margin. 

 First posterior cell very slightly narrowed, second of 

 uniform width, fourth closed with a short stalk and 

 this cell is a little longer than the discal cell, which is 

 closed nearly rectangularly. Posterior crossvein ab- 

 sent, the anal cell closed with a short stalk, ambient 

 vein ends at the end of the second posterior cell, the 

 rectangular, anterior crossvein enters the discal cell 

 slightly before the middle. Posterior branch of fourth 

 vein with thyridium at the base. Alula narrow. 



Abdomen : The abdomen at the base is nearly as wide 

 as the mesonotum and slightly wider at the end of the 

 third segment. First, second and third tergites of equal 



length, the fourth a little longer, the fifth still longer 

 and the sixth down the middle almost or quite as long 

 as the fifth and forming almost an apically rounded, 

 convex, equilateral triangle. It is completely obtuse 

 apically, cupped under and backward, concealing the 

 terminalia. Whole abdomen uniformly, densely and 

 coarsely punctured, shining black with regularly 

 spaced, minute, appressed, yellow setae. Postmargins 

 of the second to the fifth tergites with an extremely 

 narrow, postmarginal fringe of silvery micropubes- 

 cence. Sides of first tergite with 3 stout, short, white 

 bristles, middle of lateral margin of second tergite 

 with 1 stout, white bristle. 



Type. Female, Goias, Corumba, Brazil, F. Mon- 

 jolinho, November 1945, Barretto collector. Type in 

 the collection of the Departamento de Zoologia, Secre- 

 taria da Agricultura, Sao Paulo, Brazil. 



Genus Atractia Macquart 



Figures 248, 651, 1331, 1340 



Atractia Macquart, Dipteres exotiques, vol. 1, pt. 2, p. 151, 1838. 

 Type of genus: Asllus psilogaster Wiedemann, 1828, by 

 nionotypy. 



Rather small flies, characterized by the punctate, pos- 

 teriorly cupped abdomen on which the terminalia are 

 almost, not quite concealed, the restriction of tergal 

 bristles to the first 2 or 3 segments, the complete or al- 

 most complete alignment of the end vein of the discal 

 and fourth posterior cells, but more especially by the 

 characteristically attenuate, bristle-tipped, third an- 

 tenna! segment, which carries in addition a dorsal, 

 spine-bearing incision just beyond the middle. Length 

 8 to 10 mm. 



Head, lateral aspect: The face almost plane with the 

 eye on the upper portion, slightly produced and gently 

 rounded on the lower part, chiefly due to the recession 

 of the eye. The eye is of moderate length, a little more 

 narrow ventrally, strongly convex anteriorly, but 

 nearly plane posteriorly, except at the upper and lower 

 corners. The occiput is short, obliterated dorsally, a 

 little more prominent below. It has ventrally rather 

 abundant, comparatively short, fine pile which is 

 almost entirely replaced by bristles on the upper half; 

 there are 6 pairs of medium, stout bristles beginning 

 at the middle of the head; placed deeply submarginal 

 and behind the vertex and upper eye corner are 3 

 additional, quite stout bristles. The proboscis is dis- 

 tinctly longer than the face and distinctly compressed 

 laterally; it is nearly plane to the apex ventrally; the 

 oblique, obtuse apex is tapered from the dorsal side. 

 The base in lateral profile is gently swollen below and 

 bears a number of fine, long hairs ; there is a prominent, 

 medial ridge above on the basal two-thirds; the apex 

 above and below bears numerous, long, fine hairs. 

 Palpus of two segments, the first segment excavated, 

 the second rather long, slender, cylindrical, slightly 

 attenuate and bearing stout, ventral and apical bristles 



