DASTPOGONINAE 



ROBBER FLIES OF THE WORLD 



31 



larged and only stiff, ocellar pile present. The an- 

 terior eye facets slightly enlarged. 



Thorax: The thorax shining, without pollen, except 

 on the postcallus and immediately before the scutellum 

 and on the upper half of the pleuron, where only iso- 

 lated patches of pollen occur, the largest being on 

 the upper half of the mesopleuron, and with a more 

 or less continuous, narrow, oblique band of pollen from 

 the anterior sternopleuron to the posterior hypopleu- 

 ron. Mesonotum of moderate height, with dense, 

 suberect pile and poorly differentiated bristles. The 

 following complement of bristles present : 5 notopleural, 



6 to 8 supraalar, 5 postcallar, no scutellar, and 4 or 5 

 quite weak postdorsocentral bristles. Scutellum con- 

 vex, with long pile and stiff, marginal hairs. The pro- 

 pleuron and the pronotal collar bear dense, long, stiff 

 hairs, without bristles. Mesopleuron, the anterior and 

 upper posterior sternopleuron and the posterior hypo- 

 pleuron with abundant, long, stiff pile. Metapleuron 

 swollen, with long pile and 5 or 6 quite long, weak, 

 bristly hairs. Metanotal callosity pollinose only. 

 Basalare pubescent only. Tegula with short bristles. 

 Slopes of metasternum pilose. Postmetacoxal area 

 membranous. 



Legs : Hind femur distinctly stout and narrowed only 

 at the immediate base. Pile of femur on all sides dense, 

 fine, long and erect; the ventral fringe is conspicuous, 

 the lateral surface with 12 to 18 stout microtubercu- 

 late bristles, the dorsal half of the apex with a circlet 

 of 8 bristles. The hind tibia bears 6 dorsal and 6 dor- 

 solateral bristles and 5 stouter, ventrolateral bristles; 

 the apex bears 15 bristles, most of them ventral; me- 

 dial and ventral surfaces with dense appressed setae on 

 the apical half. Anterior and midfemur both stout 

 with long, fine pile. Bristles are confined to the 

 anterior surface and outer portion of the middle femur, 

 which area bears 12 stout bristles. Bristles on the an- 

 terior and middle tibia confined to a double dorsal row 

 containing approximately 8 elements. Tarsal seg- 

 ments rather short, the basitarsus about twice as long 

 as each succeeding segment. Claws sharp, strongly 

 curved at the apex, pulvillus well developed. Empo- 

 dium swollen at the base, reduced in length. 



AVings : Marginal, all posterior cells and the anal cell 

 widely open. Fourth posterior cell slightly narrowed, 

 the third correspondingly widened. Small crossvein 

 at the middle of the discal cell. Alula well developed ; 

 ambient vein complete. "Wings without pattern, nearly 

 hyaline. 



Abdomen : Cylindroid, less wide than the mesonotum, 



7 tergites present in the male, with a linear trace of 

 the eighth; 8 are present in the female, the seventh 

 not quite half as long as the sixth. Pile of abdo- 

 men abundant, stiff, more or less appressed; the side 

 of the first tergite bears numerous quite weak bristles. 

 Male terminalia large, conspicuous, not rotate. Epan- 

 drium quite large, convex, laterally extensive, fully 

 cleft to the base, with proctiger small and recessed. 

 Hypandrium forms a large broad curled protuberance 

 turned slightly upward and enclosing the interior 



535914 — 62 — pt. 1 i 



structures. The gonopod is largely enclosed by the 

 epandrium. Female terminalia recessed, inconspic- 

 uous, without spines; its ventral plate is short and me- 

 dially notched. 



Immature stages unknown. The adults frequent low 

 growing foliage at the edge of woodlands. 



Distribution : Nearctic : Echthodopa carolinensis 

 Bromley (1951) ; formosa Loew (1872) ; pubera Loew 

 (1866). 



Genus Dicolonus Loew 



Figures 3, 406, 804, 813, 1658, 1803, 1879, 1960 



Dicolonus Loew, Berliner Ent. Zeitschr., vol. 10, p. 32, 1866. 

 Type of genus : Dicolonus simplex Loew, 1866, by monotypy. 



Small or medium size flies. Eelated to Dioctria 

 Meigen and characterized by the short, dense, brushlike 

 pile, the elongate, slender antenna, with its spoon- 

 shaped microsegment, the short, robust tarsal segments, 

 the absence of bristles, the dense mystax on a rounded, 

 ventral, facial protuberance, and the short, blunt pro- 

 boscis. From all other genera in the lower Dasypo- 

 goninae, it is separated by the hairy metanotal callos- 

 ity. Female terminalia without spines. Length 10 

 to 15 mm. 



Head, lateral aspect: Length greater than usual, 

 with tumid occiput and moderately long face. The 

 face is prominent on the upper portion and still more 

 on the lower half where it extends as a conspicuous, 

 rounded elevation. Middle of face not quite plane 

 with the eye margin. The occiput is especially prom- 

 inent below due to the anterior recession of the eye and 

 the lower angle of the eye is comparatively sharp. 

 Above, the occiput continues to be swollen but in pro- 

 file is obliterated before reaching the vertex; its pile 

 dense, coarse and long; bristles absent. The proboscis 

 is exceptionally short, robust and blunt, the halves of 

 the apex slightly divergent. More than half the ven- 

 tral surface with numerous, long, fine hairs. The pro- 

 boscis is directed forward, the apex blunt. Palpus 

 clearly with a vestige of the antepenultimate segment, 

 demarcated from the following segment; end segment 

 not porate, robust, clavate with stout apical, lateral 

 apical and medial bristles. Antenna longer than the 

 head, slender, the first segment two or more times as 

 long as the second, third a little longer than the com- 

 bined length of the first two. The third segment bears 

 a single elongate, oval, spoon-shaped microsegment car- 

 rying an enclosed spine. There is some trace of a 

 shorter, second, but fused, microsegment lying between 

 the third segment and its spoon-shaped apical segment. 

 Like Dioctria the third antennal segment has an 

 elongate ventral patch of differentiated pubescence. 



Head, anterior aspect : Face for the most part pubes- 

 cent but with some nearly bare areas, one of them 

 located beneath the antenna. The prominent and swol- 

 len upper portion of the face has a tuft of dense, long, 

 fine pile and the lower elevated portion of the face has 

 still longer, more dense, slender bristles or bristly pile. 

 Subepistomal area prominent, sloping, not excavated, 



