DASYPOOONINAB 



ROBBER FLIES OF THE WORLD 



271 



wholly pubescent and with a tendency to grade into 

 the face. The face is micropubescent. In the type of 

 genus there is a single curved row of stout bristles 

 above the epistomal margin containing 4 to 5 pairs, 

 to which 1 or 2 fine hairs may be added, and above 

 on the face there are 5 short, fine hairs on either side; 

 rarely the entire lower two-thirds of the face carries 

 numerous long, stout bristles, the more central ones 

 accentuated, and all arranged in 5 or 6 fairly regular 

 rows. The antenna is attached at the upper third of 

 the head, unusually long and slender; the first segment 

 is longer than the second, the second but little longer 

 than high. The third segment is more than 2y 2 times 

 as long as the first two combined, of nearly equal thick- 

 ness throughout and dorsoventrally compressed api- 

 cally. In the type of genus the third segment is long 

 pubescent, in other species such pubescence is restricted 

 to the outer third or more ; this segment bears near the 

 outer third a distinct, dorsal incision with a basally 

 stout spine. Pile of the first segment composed of 

 several stiff hairs above, and with 1 bristle and 2 hairs in 

 some species, or in others as many as 10 bristles; the 

 second segment has 1 bristle and 1 or 2 hairs, the stout 

 bristle may be longer than the first two segments. 

 Front very slightly wider than the face below, antenna 

 slightly convergent at the vertex. The front is short, 

 pubescent, the ocellarium exceptionally large, with 

 vertical sides, large ocelli, and behind the ocelli a single 

 pair of stout, or sometimes long and slender bristles; 

 there may be 3 or 4 other fine, shorter hairs. Eye facets 

 strongly enlarged. 



Thorax: The thorax is densely, coarse, appressed 

 pubescent over the whole pleuron and in stripes or 

 isolated spots on the mesonotum. Pile of mesonotum 

 scanty, setate and appressed, a single acrostical row 

 present and the dorsocentral elements become long and 

 stout at the suture, or sometimes there is only fine, 

 nearly erect scattered pile. In the type of genus the 

 following complement of stout, long, lateral bristles 

 present: 2 notopleural, 1 supraalar, 1 postalar, 1 pair 

 of scutellar, which may increase to 3 pairs, or reduced 

 to several very short bristles, or be entirely absent. 

 Scutellum flat, but rugose and transversely wrinkled, 

 in part often thinly pubescent. Propleuron with a 

 number of long, fine hairs anteroventrally, 4 or 5 pairs 

 of weak bristly hairs on the collar, 8 to 10 slender hairs 

 or more on the posterodorsal section. There are tufts 

 of weak, bristly hairs on the anterior sternopleuron, 

 the remaining sternopleuron, hypopleuron ; in the type 

 of genus the pteropleuron is apilose but may have 3 or 

 4 slender hairs. Metapleuron with a vertical row of 6 

 long bristles behind which is a row of short hair. 

 Metanotal slopes micropubescent only; lateral meta- 

 sternum with pile ; ventral metasternum chitinized with 

 a separate band of chitin and several long, fine hairs; 

 postmetacoxal area membranous ; the tegula may have 

 a few bristles. Prosternum dissociated. 



Legs: The femora are moderately thick; the hind 

 femur is slightly dilated from the base. Pile of legs 

 scanty, short and appressed and quite scanty ventrally 



on the femora where it is long, fine and erect. Bristles 

 are especially well developed and tend to be long, 

 basally stout, oblique and attenuate ; the type of genus 

 shows the following complement: hind femur with 1 

 short lateral at the basal third, 1 dorsolateral and 1 

 mediolateral at the apex, and 1 subdorsal a short dis- 

 tance from the apex. Ventral aspect of this femur on 

 the basal third characteristically with a pair of excep- 

 tionally long, erect bristles located not far apart. Hind 

 tibia with 4 dorsal elements becoming progressively 

 longer, 2 long lateral before and beyond the middle, 

 3 still longer ventrolateral beginning just before the 

 middle; the apex has 1 dorsolateral, 3 lateral, 1 medial, 



2 or 3 ventral bristles. On the hind tibia there is a 

 brush of setae beginning at the basal third, becoming 

 more accentuated distally and continued on to the tarsus 

 with ranked pile. Middle femur with exactly similar 

 bristles to the hind pair except that there is only a 

 single, much less prominent basiventral bristle. The 

 middle tibia has 3 exceptionally long, stout, antero- 

 dorsal, sometimes 4 or 5, 3 to 5 short posterodorsal, 3 

 to 4 extraordinarily long ventral, and 5 to 8 more slen- 

 der, long posterior bristles. Anterior femur with a 

 small anterior apical bristle, 5 short dorsal, a like num- 

 ber of anterodorsal, 5 or 6 short posterior, and at least 



3 or 4 quite long, posteroventral bristles. Anterior 

 tibia at apex with subapical bristles and at the apex 

 proper with a ventrolateral, stout, curved spine but 

 without corresponding basitarsus modification and 

 without basal lobe. All tarsi end in stout, sharp claws, 

 bent chiefly at the apex, large pulvilli, and an 

 empodium swollen at the base. 



Wings : Marginal and all posterior cells widely open, 

 anal cell widely open or occasionally closed in the 

 margin. Anterior crossvein at or beyond the middle 

 of the discal cell. Alula of moderate width ; ambient 

 vein complete. 



Abdomen: The abdomen is nearly or quite as wide 

 as the mesonotum, rather convex, and with the sides 

 curled downward conspicuously; the middles of the 

 tergites are somewhat flattened, the apical portion of 

 the abdomen is gently tapered. First tergite with 2 

 to 5 bristles, stout or slender. Pile of abdomen moder- 

 ately abundant, fine and suberect, longer and erect 

 laterally but scanty. Male with seven tergites, the 

 seventh is a third to a fourth as long as the sixth; 

 rarely there may be only six tergites. Female with 

 eight tergites, the seventh one-half to two-thirds as long 

 as the sixth and the eighth a little shorter. Male termi- 

 nalia rather short, rotate one- fourth to the right. The 

 epandrium is notched apically or with a fissure or cleft 

 extending nearly to the base ; in a few species extending 

 entirely to the base. Female with 7 pairs of blunt, 

 spoon-shaped spines and with 3 or more distinct, stout, 

 marginal bristles on the lower structures. The last 

 sternite has an oval cleft on the outer half. 



Distribution: Nearctic: Taracticus niger Macquart 

 (1838) ; octopunctatus Say (1823) [=fiavipes Coquil- 

 lett (1904), rufipes Jones (1907)]; paulm Pritchard 

 (1938) ; ruficaudus Curran (1930). 



