DASTPOOOXINAE 



ROBBER FLIES OF THE WORLD 



105 



4. Third antennal segment quite large, distinctly wider than 



either basal segment and approximately twice as long as 

 wide ; occipital and pionotal bristles stout ; 2 notopleural 

 and 2 supraalar bristles ; 2 pairs of scutellar bristles ; 

 anterior and middle femora rather swollen. 



Wuaistonina Back 

 Third antennal segment stout ; if wider than the basal seg- 

 ment it is much longer than these 5 



5. Three submarginal cells Cryptopogon White 



Two submarginal cells 6 



6. Pulvilli absent ; face usually densely beset with wide scales. 



Rhadinus Loew 

 Pulvilli present 7 



7. With a single bristle above the wing and the apex of the 



palpus pilose ; flies of comparatively large size. 



Neopooon Bezzi 



Two bristles above the wing ; apex of palpus hare. Usually 



small flies 8 



8. Mystax generally and loosely distributed ; face chiefly bare; 



ocellar setae weak or lacking . . Echinopoqon Bezzi 



Mystax tectiform and shieldlike, condensed across the oral 



margin 9 



9. Fourth posterior cell closed with a long stalk or petiole; 



ocellar bristles well developed . . Stichopogon Loew 

 Fourth posterior cell narrowly closed or closed in the mar- 

 gin ; ocellar pile abundant but soft 10 



10. Mystax horizontal and curling downward ; confined to oral 

 margin or lower fourth of face; second submarginal cell 

 long and narrow at apex .... Dichropogon Bezzi 

 Mystax inclined nearly vertically downward, extending up 

 nearly to the base of antenna ; second submarginal cell 

 widely flared, its apex trumpet-shaped. Rather robust, 

 densely pilose flies, short pilose on the thorax but long 

 pilose (especially in males) on the basal half of the 

 abdomen. They are 10 to 15 mm. in length. 



Clinopogon Bezzi 



Genus Stichopogon Loew 

 Figures 53, 509, 929, 938 



Stichopogon Loew, Linnaea Entomologica, vol. 2, p. 499, 1847. 



Type of genus : Dasypogon elegantulus Wiedemann in Mei- 



gen, 1820. Designated by Back, 1909, the third of 4 species. 

 Stilopogon A. Costa, Atti Roy. Accad. Sci. Napoli, ser. 2, vol. 1, 



p. 62, 1SS3. Type of genus : Stilopogon aequccinctus A. 



Costa, 1SS3, by monotypy. 



Stichopogon has 3 subgenera, Dichropogon Bezzi, 

 Echinopogon Bezzi, and Cin/ptopogon White. 



Minute flies of dark color and usually banded with 

 pale pollen. Characterized by the single row of mat- 

 like, epistomal bristles, the very widely divergent front 

 and vertex, the short style attached to the third antennal 

 segment, the greatly enlarged, anterior eye facets and 

 the downward turned, hoodlike cover of the male termi- 

 nalia formed by the ninth tergite. Lateral metasternum 

 without pile. Length 3 to 8 mm. 



Head, lateral aspect: The head is comparatively 

 long with the eye strongly convex anteriorly and anter- 

 oventrally recessive to a marked extent. The face is 

 extremely short, and in profile only appears as a low 

 elevation near the epistoma, or is at least confined to 

 the lower half. Occiput prominent below and in the 

 middle obliterated dorsally by the posterior develop- 

 ment of the eyes ; it is everywhere pollinose with fine, 

 dense pile. On the upper occiput there is a transverse 

 row of weak bristles varying from 3 to 6 on each side. 

 Proboscis stout and cylindrical, with blunt apex; it is 

 sometimes narrowed apically or dorsoventrally com- 

 pressed at apex. It bears only minute hairs at the 

 apex and either short or long abundant pile on the 

 ventral portion of the base. Palpus with two seg- 

 ments ; the first minute, the second more slender, cylin- 

 drical, porate, naked, and with a few minute 

 ventrolateral hairs near the base. The antenna is at- 

 tached near the middle of the head, comparatively small 

 but slender, the short first two segments are subequal ; 

 the third segment is nearly twice as long as the first 



two and with a short spine-tipped style about half as 

 long as the third segment. 



Head, anterior aspect: Face below antenna about 

 one-fifth the head width or even less, divergent below, 

 pollinose with a few scattered hairs in the middle in 

 some species and always with a rather matted close-set 

 mystax of moderately stout bristles transversely placed 

 and directed obliquely downward. Front with a few, 

 scattered stiff hairs and together with the vertex 

 strongly divergent, but only moderately excavated. 

 The ocellarium varies from extremely low to about 

 twice the ocellar height; it has either a few divergent 

 hairs or occasionally a pair of weak bristles. Anterior 

 eye facets strongly enlarged. 



Thorax: The mesonotum often shining in part or 

 wholly pollinose; the pile is scanty, stiff and undifferen- 

 tiated. The mesonotal complement of bristles consists 

 of 1 notopleural, 1 supraalar, 1 postalar, and on the 

 scutellar margin 1 or 2 rows of long, stiff hairs and 

 a little additional pile on the disc. Pleuron everywhere 

 pollinose with minute hairs on the upper sternopleuron, 

 the posterior mesopleuron and on the propleuron we 

 find either very scanty pile or sometimes abundant long 

 pile ; metapleuron with a vertical row of weak bristles. 

 The squama may be reduced to a linear trace with no 

 pile or in some American species may be short with a 

 fine fringe of pile. Lateral slopes of the metasternum 

 without pile; ventral metasternum widely chitinized 

 with scattered hairs; postmetacoxal area membranous. 

 Prosternum not dissociated. 



Legs: The femora are rather stout, especially the 

 anterior and middle pair, their bristles weak and short 

 as a rule. On the hind femur are 3 weak dorsolateral 

 bristles or as many as 9; dorsal apex with a pair of 

 minute bristles ; middle femur with 2 apical anterodor- 

 sal and posterodorsal bristles; anterior femur with 1 

 posterodorsal and one anterodorsal bristle. Bristles 

 are slightly better developed on the tarsi and tibiae and 

 may be inconspicuous and short or comparatively long 

 and slender. On the hind tibia are 6 dorsal and 2 

 anteroventral, the apex with 6 to 8 bristles. Middle 



