DASTTOGONINAB 



ROBBER FLIES OF THE WORLD 



129 



to the strong recession of the eye. The occipital pile is 

 coarse and bristly behind the proboscis and medially ; 

 the entire occiput from bottom to vertex with an ex- 

 tensive band of stout, numerous, rather long bristles. 

 The extent of the eye ventrally is greatly reduced leav- 

 ing it pointed and angular. The proboscis is small and 

 slender, cylindrical, tapered to an obtuse point and ex- 

 tending well beyond the face. The basal half below is 

 beset with scattered bristly hairs, the apex with short, 

 stiff hair. Palpus clearly of two segments, the first 

 segment hemicylindrical and excavated, the second 

 short, robust with apical pore and bristly pile. The 

 antenna is attached at or above the upper fourth of 

 the head and elongate, distinctly longer than the head, 

 the second segment is one-half or one-third the length 

 of the first, and the third segment at least twice the 

 length of the first two combined. Medial surface of the 

 third segment with extensive sensory areas, the apex 

 with a short, semifused microsegment carrying an 

 apical pit and spine; less commonly with two small, 

 slender microsegments. 



Head, anterior aspect: The head is nearly circular. 

 The face below the antenna is narrow, one-fifth or less 

 the total head width and rather strongly divergent 

 below, its surface very finely pubescent, the upper half 

 medially has short, stout bristles or bristly setae. The 

 lower and slightly produced half has a few, scattered, 

 long, quite stout bristles, and some smaller, more slender 

 ones, extending laterally down the sides of the oblique, 

 concave subepistoma. Front short, small and pollinose, 

 characteristically with an ocular row of 3 or 4 unusu- 

 ally stout, long bristles. The front is a little wider than 

 the upper face and slightly converging above. The ver- 

 tex shows little and sometimes no excavation. The ocel- 

 larium is quite low with several pairs of slender bristles 

 and an additional postocellar row on each side. An- 

 terior eye facets scarcely enlarged. 



Thorax: The mesonotum is bare in appearance due 

 to the reduced pile, which consists of stout, short, scat- 

 tered, suberect setae. No differentiated acrostical or 

 dorsocentral bristles present. The lateral complement 

 of bristles consists of 2 to 8 humeral, 3 to 5 posthumeral, 

 and a like number of notopleural and also of supraalar 

 and postalar bristles. Scutellum with 3 to 5 pairs of 

 bristles, the surface convex and otherwise bare. Pleu- 

 ron, except for the anterolateral element, characteris- 

 tically best with many, long, stout bristles. The anter- 

 olateral element has a tuft of fine pile. Presternum 

 dissociated. Mesopleuron, pteropleuron, and hypo- 

 pleuron apilose. Sternopleuron with a few, fine hairs. 

 Metapleuron with reduced, bristly hairs and sometimes 

 1 or 2 stout bristles. Lateral slopes of the metasternum 

 apilose, the ventral metasternum with 2 or 3 hairs, the 

 postmetacoxal area membranous. 



Legs: The femora are stout, the anterior pair 

 slightly swollen towards the base. Bristles are un- 

 usually abundant, the pile coarse, dense, appressed se- 

 tate. On the hind femur there are 5 to 8 dorsolateral, 

 7 to 16 ventrolateral, and 7 or 8 ventromedial bristles, 

 besides several medial bristles. The bristles are nu- 



merous on the ventral and posterior surface of the 

 anterior femur and the ventral, anterior surfaces and 

 posteroventral surfaces of the middle femur. There 

 are 10 to 12 of these stout elements on these ventral 

 surfaces and 3 to 5 on the anterior surface of the 

 middle femur, 2 posteriorly near the apex. Anterior 

 surfaces on the anterior and middle coxae and lateral 

 and ventral surfaces on the posterior coxa with numer- 

 ous stout bristles. Tibial bristles of only normal num- 

 bers except on the anterior four. The dorsal surface 

 of the hind tibia has 5 in each row but there are 12 

 ventromedial bristles present and 5 ventrolateral ones. 

 Anterior tibia with 4 rows and middle tibia with 5 

 rows of stout, only moderately long bristles, usually 

 containing about 7 elements each. Protibial apex 

 without spine. Claws long, stout, rather sharp, the 

 pulvilli well developed, and the empodium bladelike. 



Wings: The marginal cell is widely open. Fourth 

 posterior cell closed in the margin or closed with a 

 stalk. Anal cell narrowly closed or open. Wings gen- 

 erally dark smoky blackish or bluish black. 



Abdomen: The abdomen is comparatively elongate 

 and sometimes longer than the wings. At the base it. 

 is about as wide as the mesonotum and gently tapered 

 beyond. Males with 7 tergites, the eighth completely 

 concealed. Females with 8 tergites, the last being 

 about half as long as the seventh. Pile of abdomen 

 scanty, setate, and appressed. Bristles restricted 

 laterally to the first 2 or 3 tergites where they may be 

 stout and numerous especially on the first 2 tergites. 

 Male terminalia not rotate, the epandrium widely di- 

 vided into distinct, elongate forceps of moderate size. 

 The gonopod is smaller, the hypandrium moderately 

 large. Females with 6 pairs of long, stout spines on 

 the acanthophorites. 



Distribution : Nearctic : Ospriocerus abdominalis Say 

 (1824) [ = aeacides Loew (1866), aeacus Wiedemann 

 (1828), spathulatus Bellardi (1861)] ; eutrophus Loew 

 (1874) ; minos Osten Sacken (1877) ; nitens Coquillett 

 (1904) [=monki Bromley (1934)]; parksi Bromley 

 (1934) ; rhadamanthus Loew (1866) ; ventralis Coquil- 

 lett (1898). 



Neotropical: Ospriocerus diversus Williston (1901). 



Genus Galactopogon Engel 



Figures 156a, 458, 915, 924, 1824, 1848, 1865, 2030 



Galactopogon Engel, in Lindner Die fliegen der palaearktlschen 

 Region, pt. 24, Asilidae, p. 273, 1929. Type of genus: 

 Galactopogon liispidus Engel, 1929, by original designa- 

 tion. 



Characterized by the nearly circular head and nar- 

 row face and the absence of pulvilli. From Gonioscelis 

 Loew it is also separated by the absence of the facial 

 gibbosity. The bristles of the face are exceptionally 

 long, dense, and close-set. While there are numerous 

 stout bristles on the anterior coxa and femur, more than 

 ordinarily found, the femur lacks the extrusive proc- 



