DASYTOGONINAE 



ROBBER FLIES OF THE WORLD 



45 



which turn obliquely downward and enclose the rela- 

 tively small gonopod. The divergence of these struc- 

 tures exposes the paired, large, elongate, spatulate, 

 bluntly rounded, apposed proctiger. Hypandrium 

 greatly reduced. The whole terminalia usually cov- 

 ered and obscured by dense mats of very long, coarse 

 pile and bristly hairs, arising both from its own struc- 

 tures and from the end tergites ; eighth tergite usually 

 recessed and hidden. Female terminalia elongate 

 and rather compressed dorsoventrally with sharp, thin, 

 lateral edges ; the seventh tergite is slightly longer than 

 the eighth ; acanthophorites and spines absent. 



Distribution: Australian: Phellus glaucus Walker 

 (1851) ; olgae Paramonov (1953) ; piliferus Dakin and 

 Fordham (1922). 



Genus Obelophorus Schiner 



Figures 28, 401, 805, 814, 1654, 1877 



Obelophorus Schiner, Verb, zool.-bot. Ges. Wien, vol. 16, p. 672, 

 1866. Type of genus : Dasypogon terebratus Macquart, 

 1849, by original designation. 



Very large robust flies. Characterized by convex pro- 

 tuberant face with abrupt ridge shortly below the an- 

 tenna. The swollen part of the face has a dense, wide, 

 medial band of long bristles and bristly pile. The ab- 

 domen, the posterior, anterior and ventral part of the 

 thorax are characterized by dense matted pile. The legs 

 are also provided with brushes of bushy pile. The genus 

 is also recognized by the appendiculate vein at base of 

 the second submarginal cell and the rather pointed wing 

 which is broad basally, together with the long, slender 

 ovipositor of the female. These flies are unquestionably 

 related to Phellus Walker from Australia, because the 

 antenna and the wing pattern are virtually identical. 

 The chief differences lie in the shorter abdomen and 

 different character of the female terminalia and es- 

 pecially in the short palpus; in Phellus the palpus is 

 nearly as long as the proboscis and slightly sigmoid. 

 Length 33 to 45 mm. 



Head, lateral aspect : Face strongly protuberant, ex- 

 cept on the upper fifth, which is only shortly produced 

 and plane with the eye margin. Below the face is 

 abruptly produced and the lower portion is gently con- 

 vex. The eye is comparatively short, more narrow be- 

 low, due chiefly to a moderate anteroventral recession. 

 The occiput is well developed, obliterated at a point 

 shortly below the vertex ; laterally it becomes more ex- 

 tensive a short distance back from the eye margins ; it is 

 quite prominent ventrally, accentuated by the eye reces- 

 sion. Pile of occiput coarse and dense, short on the 

 upper half, becoming progressively longer below ; bris- 

 tles are restricted to the upper medial corners of the 

 eye, where there are some four pairs which are subpro- 

 clinate. Proboscis directed nearly forward or slightly 

 downward; it is stout, robust, subcylindrical with ob- 

 tuse apex ; its height is increased by the unusually prom- 

 inent high medial ridge ; it bears a medium crease be- 



low ; it has fine pile at the apex and below and numer- 

 ous, long, stiff hairs ventrally on the basal two-thirds. 

 Palpus clearly of two segments, the first hemicylindri- 

 cal and excavated, the second nonporate and bearing 

 numerous bristly hairs extending upon the apex. An- 

 tenna attached at the upper third of the head ; rather 

 slender, approximately the same length as the head. 

 The first segment is a little longer than the second and 

 more robust, the third 2y 2 times as long as the first two 

 combined, slightly dilated beginning at the basal third, 

 gently tapered near the apex, and carrying a stout, ta- 

 pered microsegment twice as long as its width and pro- 

 vided with a short, distinct, dorsal spine. The first seg- 

 ment more robust than the second, and carries abundant, 

 long, bristly pile on all sides except the middle and 3 

 slender bristles below. Second segment with 3 or 4 

 short bristles dorsomedially and 2 ventromedially. 



Head, anterior aspect : Face below antenna less than 

 one-third the head width and divergent below. The 

 subepistomal area is short, oblique, well concealed by 

 the palpus and the mystax. The face is thickly, 

 coarsely appressed pubescent and bears, except close 

 to the eye margins and upon the plane area beneath 

 the antenna, a rather dense mystax of stiff hair with 

 slender intermixed bristles of progressively increas- 

 ing length towards the lower part of the face. Front 

 short, not pubescent, with a tuft of dense pile 

 above and lateral to the antenna; sides of the front 

 with a broad band of numerous, long, slender bristles. 

 The vertex is rather deeply excavated, with strongly 

 sloping sides, the ocellarium small, with steep sides and 

 large ocelli, and bears across the middle and posterior 

 portion 10 to 12 pairs of laterally divergent, slender 

 bristles. Eye facets scarcely enlarged. 



Thorax : The mesonotum and humerus are set with 

 abundant, stiff but fine, suberect pile, bristly in char- 

 acter, leaving much of the mesonotum bare and shin- 

 ing; it is not quite twice as long as high. The margins 

 bear the following complement of rather short bristles 

 of medium strength : 2 weak posthumeral ; 4 notopleural 

 with sometimes 4 or 5 additional very slender bristles 

 lying between these, and 7 or 8 supraalar, most of 

 them slender. On the postalar is abundant stiff pile 

 with about 18 long bristly hairs intermixed. Scutel- 

 lum with dense long pile on the disc and the upper 

 margin; the lowermost elements might be considered 

 very weak bristles; surface convex. The propleuron 

 everywhere bears dense, long tufts of matted, fine pile ; 

 bristles absent on the collar, but thick, long pile present. 

 Bristles absent everywhere on the pleuron; the pos- 

 terior upper mesopleuron with a dense tuft of fine, 

 medium length pile; the anterior and upper posterior 

 sternopleuron and the metapleuron, each bear dense 

 tufts of pile; pteropleuron and hypopleuron apilose. 

 Metanotal slopes strongly bullose but micropubescerit 

 only. Sides of metasterniun pilose, the metasternum 

 with long pile, the postmetacoxal area membranous but 

 reduced in extent to a very small triangle; anterior 

 basalare with a conspicuous tuft of long dense pile. 



