DASTPOGONINAB 



ROBBER FLIES OF THE WORLD 



149 



Distribution: Ethiopian: Spanurus compressus 

 Karsch (1886) ; pallidus Ricardo (1925) ; pulverulentus 

 Loew (1858) ; tellinii Bezzi (1906). 



Genus Bathypogon Loew 



Figures 111, 167, 462, 511, 1017, 1026, 1703, 1903, 2026 



Bathypogon Loew, Bemerkungen iiber die Familie Asiliden, p. 

 13, 1851. Type of genus: Dasypogon asiliformis Loew, 

 1851, by nionotypy. 



Bathypogon has one subgenus, Creolestes, new 

 subgenus. 



Small to rather large flies, characterized by the prom- 

 inent bristles, unspined protibial apex, the numerous 

 facial bristles, the generally shortly produced face, but 

 still more by the rather short wing and its characteristic 

 venation. The anterior branch of the third vein arises 

 abruptly from the straight base of the third vein and 

 ends close to the second vein and far from the wing 

 apex; the first submarginal cell is narrowed on the 

 margin. Also the fourth posterior cell is closed with 

 a long stalk and usually but not always the end vein 

 of this cell and the lower end vein of the discal cell are 

 nearly or quite aligned. Length occasionally as little 

 as 10 mm. but more often 15 mm. and rarely as much 

 as 30 mm. 



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

 the face usually a little produced and gently gibbous 

 over the middle. The length of the area beneath the 

 antenna is very short. The eye is generally greatly 

 narrowed and pointed below, due to both anterior and 

 posterior recession. Occiput moderately developed, ex- 

 cept at the immediate vertex, its ventral pile is dense, 

 long and quite fine; bristles begin at the lower third, 

 and are numerous and below the middle occupy two 

 or three rows. At the middle and above they form a 

 very regular, single row and in addition there is a 

 prominent cluster on each side behind the vertex hav- 

 ing up to 10 bristles. Proboscis robust, of moderate 

 length, on the outer fourth it is tapered above and 

 below to a blunt point. It has a long carina reaching 

 nearly to the apex and much long, coarse pile, ventrally 

 on the basal half. Palpus of two segments, the first 

 segment excavated, the second cylindrical with slender, 

 apical bristly hairs and considerable ventral pile. The 

 antenna is attached a little above the middle of the 

 head, scarcely as long as the total head length but a 

 little longer than the eye. The first segment is twice 

 as long as the second; second segment beadlike; first 

 segment with numerous, long, coarse hairs or ventral 

 bristles. The third segment is a little wider through 

 the middle than the second segment or than its base or 

 apex, and sometimes it may be considerably dilated 

 beyond the middle. This segment bears 2 micro- 

 segments, the first quite short, the second several times 

 as long with a spine at apex. 



Head, anterior aspect: The head is not very wide, 

 only a little wider than high; the face is about one- 

 fifth the head width below the antenna and distinctly 



but moderately divergent below. The face is every- 

 where coarsely pubescent, usually without pile, but 

 with a wide, medial triangle of numerous, exceptionally 

 stout, long, pale or sometimes black bristles. The lower 

 elements reach beyond the proboscis. In an occasional 

 species the elements are distributed in the same way, 

 but are so slender that they might be regarded as very 

 coarse pile instead of bristles. Front slightly diver- 

 gent, a little convergent at the vertex. The front is 

 sunken, pollinose, with a submedial row of 4 or 5 

 bristles. Vertex moderately excavated with slanting 

 sides, large ocellarium, with nearly vertical sides and 

 2 or 3 stout bristles between the ocelli; a like number 

 of pairs behind the ocelli. Anterior ocellus enlarged. 

 Eye margin along the vertex with 3 stout bristles. 

 Subepistomal area moderately large, concave, polli- 

 nose, oblique. Anterior eye facets considerably en- 

 larged. 



Thorax: The thorax is pollinose with abundant, fine 

 pile, much of it setate and widely distributed. Medial 

 pile is present, but not differentiated. Dorsocentral 

 bristles are differentiated only posteriorly where they 

 are from 3 to 5 in number and are long and stout. 

 Humerus with scattered setae, the lateral complement 

 all long and stout : 1 posthumeral, 2 or 3 notopleural, 

 1 or 2 supraalar, 2 postalar, and 2 pairs on the scutel- 

 lum. Disc of scutellum flattened, pollinose, usually 

 without pile, but sometimes with long, coarse or fine 

 hair. Anterior collar generally with 7 or 8 pairs of 

 long spikelike bristles; the lateral pronotum has only 

 dense pile. Cervical sclerite and the posterior lateral 

 propleuron with dense, fine pile, the anterior element 

 with 3 stout, bristles and much pile, Pleuron generally 

 pollinose; metapleuron with 1 to 6 or more long, stout 

 bristles, and much similar, long, bristly pile. All coxa 

 laterally with long, stout bristles. Remainder of 

 pleuron without pile, except a few short hairs some- 

 times on the lower sternopleuron. Lateral and ventral 

 metasternum pilose ; postmetacoxal area membranous. 



Legs: The femora are rather short and stout, the 

 anterior and middle pair distinctly swollen over the 

 middle and towards the base; their pile is abundant, 

 subappressed and setate. Bristles of both femora and 

 tibiae are stout, long and prominent; hind femur with 

 4 lateral, a pair of dorsomedial bristles at apex; the 

 middle, femur has at the apex a pair of posterodorsal 

 and 2 or 3 anterior bristles. Anterior femur with 1 

 bristle on either side near the apex and 1 posterior 

 bristle at the outer third. The hind tibia has 3 promi- 

 nent bristles in both the dorsomedial and dorsolateral 

 rows, 4 ventrolateral and 1 medial bristle. Middle 

 tibia with approximately the same number of bristles 

 in like rows and with also 1 ventral bristle. Anterior 

 tibia similar but with 5 bristles in the anterodorsal row 

 and the posterodorsal row. Protibial apex without 

 spine ; the apical circlet of bristles in common with the 

 other tibiae is exceptionally long and set a considerable 

 distance from the apex. Tarsal bristles stout and long. 

 Claws only moderately sharp, pulvilli long, empodium 

 bladelike. 



