DASTFOG0N1NAE 



ROBBER FLIES OF THE WORLD 



49 



narrowly open, or almost closed. The second basal cell 

 ends in 2 veins, the upper end vein of the discal cell 

 short and in the type of genus almost eliminated. 



Abdomen : The abdomen is broad, of robust form and 

 towards the base only slightly convex, becoming more 

 cylindroid distally. The pile is scattered and setate, 

 appressed or erect. The type of genus is pollinose; 

 some species are bare except for lateral spots, or the 

 surface sometimes coarsely punctate. Males with 6 well 

 developed tergites, the seventh and eighth short or in 

 some cases nearly concealed. Females with 6 well de- 

 veloped tergites, the remainder recessed beneath the 

 sixth. Sides of the first tergite with a single, very 

 stout, tuberculate bristle and some fine hairs. Male 

 terminalia rotate one- fourth to the left, the epandrium 

 undivided, arched into a hemicylinder and nearly trun- 

 cate. Gonopod large, subcylindroid, and a little nar- 

 rowed apically. The interior structures are exposed 

 below because of the reduced or nearly absent hypan- 

 drium. Female with the last 3 tergites laterally com- 

 pressed and protrusive; the ventral plate is likewise 

 very strongly compressed and almost as long as the dor- 

 sal portion. Acanthophorites and spines absent ; some 

 species have short, stout spinous setae of a different 

 type. 



Distribution : Australian : Chrysopogon albopuncta- 

 tus Macquart (1844) ; crabroniformis Roeder (1881) ; 

 conopsoides Fabricius (1775) ; fasciatus Ricardo 

 (1912) ; Komi Hardy (1934) ; mulleri Roeder (1892) ; 

 nigricans White (1914) ; pallidipennis "White (1917) ; 

 punctatus Ricardo (1912) ; queenslandi Ricardo (1912) ; 

 rubripennis White (1917) ; rufulus White (1914) ; 

 splendidissinvus Ricardo (1912). 



Genus Opseostlengis White 



Figures 8, 407, 820, 829, 1646, 1647, 1926, 2006 



Opseostlengis White, Papers Proc. Roy. Soc. Tasmania, 1913, 

 p. 269, 1914. Type of genus : Opseostlengis insignis White 

 1914, by monotypy. 



Flies which are unusually bare and with greatly re- 

 duced bristles, the abdomen comparatively wide and 

 flattened, with dense short microsetae. Related to 

 Chrysopogon Roeder; the antenna bears a short, 

 straight, conical, spinous subsegment, and like that 

 genus there is a single, stout, tuberculate, notopleural 

 spine. Length 15 to 20 mm. 



Head, lateral aspect: Face short above, slightly more 

 prominent below. Occiput narrow in profile but more 

 swollen near the foramen. Pile moderately long and 

 stiff and everywhere bristly. On the occiput opposite 

 the lower corner of the eye there is an especially 

 abundant patch of long, slender bristles. The probos- 

 cis is similar to that of Chrysopogon. Palpus clearly 

 of 2 segments, the second segment arising at a slight 

 angle, short, distally swollen, with a large gaping pore ; 

 the first segment is hemicylindrical and excavated. 

 Antenna attached at the upper fourth of head, of mod- 

 erate length, the first 2 segments of equal length, the 



third with its short style, approximately equal to l 1 /^ 

 times the length of the first 2 segments combined. The 

 third segment is laterally compressed, broadly oval, 

 a little narrowed towards the base, again narrowed 

 at the immediate apex and bearing a rather large, but 

 short sharp conical spine. 



Head, anterior aspect: Head width l 1 /? times the 

 height. Face below antenna two-sevenths head width, 

 expanding below to one-third head width. The face is 

 pubescent without pile ; epistomal margin with a single 

 row of very stout, closely adjacent, slightly curved, 

 rather long, stout bristles directed obliquely down- 

 ward. Front slightly divergent, the vertex equally 

 slightly convergent. Front bare except laterally and 

 below, with medial fissure, and bearing on each side 6 

 weak bristles. Vertex moderately excavated, the ocel- 

 lar protuberance large with slanting sides and bearing 

 6 or 7 pairs of short, weak bristles. Eye facets cen- 

 trally enlarged 



Thorax: The thorax with fine micropubescence, the 

 mesonotum bears scanty pile, fine and setate, a sparse 

 acrostical row with apilose stripe on either side. The 

 dorsocentrals are scanty opposite the humeri, but 

 abundant and short beyond, becoming no longer pos- 

 teriorly. Humerus with some stiff pile. Notopleuron 

 with a stout, sharp spine set in a heavy circular pro- 

 trusive base. Supraalar region with numerous stout 

 bristly setae, postalar region similar and with 1 weak 

 short bristle. Scutellar margin with a row of 20 or 

 more short, stiff, bristly setae, a few others scattered 

 over the transversely ridged, rugose, pubescent surface. 

 Propleuron with rather abundant pile on the ventral 

 element. Collar with weak bristly pile. Mesopleuron 

 with numerous, short, bristly setae; others present on 

 the sternopleuron but pile absent on the peteropleuron 

 and hypopleuron. Metapleuron with 5 or 6 weak slen- 

 der bristles; metanotal slopes unusually bullose, with- 

 out pile. Metasternal slopes with numerous, long, fine 

 hairs; postmetacoxal area membranous. 



Legs: The legs are unusually stout, the thickening 

 extending more or less throughout the femora, but 

 slightly greater distally on the hind pair. Bristles 

 numerous but for the most part short. All of the coxae 

 with weak, bristly pile only. Hind trochanter with 4 

 stout, spinous bristles. Pile of hind femur scanty, 

 flat appressed, fine and setate, with 4 or 5 erect, slender 

 hairs below and some appressed setae distally. This 

 femur bears a cluster of 3 or 4 short, stout bristles 

 medially at the apex, 1 long one at the dorsolateral 

 apex, 2 short bristles laterally at the apex and besides 

 it bears a row of 10 exceedingly stout, sharp, tuber- 

 culate, almost conical, spinous bristles on the middle of 

 the lateral margin; they bear 9 similar elements ven- 

 trally and 6 similar, shorter bristles in the middle 

 medially. Hind tibia bears short, stout bristles 

 as follows: 5 or 6 dorsal, 6 dorsomedial, 6 somewhat 

 longer lateral, 3 medioventral, and 2 ventrolateral. 

 Anterior femur with 1 bristle anteriorly at the basal 

 third, an oblique row of 5 anteriorly at the apex, 2 

 close together posteriorly in the middle, and 8 ventrally 



