ROBBER FLIES OP THE WORLD 



495 



laterally. Females with seven tergites, the eighth, 

 while quite similar in character to the seventh in both 

 pollen and pile, is very strongly pinched and laterally 

 compressed. The ninth and tenth female tergites are 

 wide laterally or broad, very short and form a short, 

 roimded, clublike structure; the lateral margin of this 

 club bears a dense fringe of downward curled, stiff pile. 

 Male terminalia large, not rotate. The eighth sternite 

 is long with a pair of long, posteriorly extended, cla- 

 vate, knoblike processes which carry a tuft of posterior- 

 ly long, close-set, bristly pile curving inward medially. 

 Pile of the abdomen coarse, flat appressed in both sexes, 

 with a little more erect, somewhat longer jjile on the 

 sides of the second and third tergites and with a long, 

 dense tuft of pile on the sides of the first tergite. Sides 

 of first tergite protuberant, with 1 or 2 weak bristles or 

 none; first sternite without pile, the remainder with 

 only short, fine, scanty pile, more or less appressed. 



Distribution: Neotropical: Philonerax mucidus 

 Walker (1837). 



Genus Lochmorhynchus Engel 



FIOURES 206, 716, 732, 1420, 1429, 1437, 1446, 2203, 2217, 2363, 



2494 



Lochmorliynchus Engel, Konowla, vol. 8, p. 459, 1930. Type of 

 genus : Proctacantlius sencctus Wulp, 1882, by original 

 designation. 



Quite large flies belonging to the group in which both 

 branches of the third vein end distinctly above the wing 

 apex. Characterized by the moderately swollen middle 

 and anterior femora and the strongly expanded costa in 

 the male and the marginal and submarginal cells in 

 both sexes. The third antennal segment is short with 

 a long, straight style. The face is quite gibbose ven- 

 trally and abruptly produced just above the middle of 

 the face. Epistomal bristles prominent. Female ovi- 

 positor long and cylindrical. Length 30 mm. 



Head, lateral aspect : The face is strongly gibbose on 

 the lower three-fifths, developed abmptly with an up- 

 per ledge, the upper face being produced only shortly. 

 The eye is strongly convex anteriorly, gently convex 

 behind with moderate, anteroventral recession which 

 includes the lower third of the eye. The occiput is 

 rather prominent throughout, widest submedially, 

 sloping and rounded down the eye margin; pile of 

 occiput dense, but rather fine on the ventral half, the 

 pile is moderately long and set close to the eye margin. 

 Bristles begin at the middle of the liead and are stout 

 and black, with 16 to 20 pairs present, all rather 

 straight and comparatively blunt; there is some fine, 

 long pile dorsally on the occiput. Proboscis stout, di- 

 rected chiefly downward, of moderate length, a little 

 attenuate above and below on the apical fourth; the 

 apex is bluntly rounded with only a few minute hairs, 

 the ventral and ventrolateral surface is for at least two- 

 thirds of the length densely beset with long pile. 

 Palpus elongate, slender, with numerous, bristly hairs 

 and some stiff, apical bristles. The antenna is attached 



a little above the middle of the head in profile and com- 

 paratively short. The first segment is more than twice 

 as long as the short second segment, the third segment 

 is quite short but broad and rather strongly compressed 

 laterally, more or less bluntly pyriform, with a very 

 shoi-t, but distmct microsegment and a stout, straight 

 spine or a bristle-tipped style, a little stouter basally 

 and a little longer than the combmed length of the three 

 segments. Ventral and lateral pile of the first segment 

 composed of numerous, only moderately long, white 

 bristles, or bristly pile, somewhat shorter but abundant 

 pile dorsally; second segment with an apical ring of 

 setae, except medially. 



Head, anterior aspect : The face below the antenna is 

 a little more than a fourth the head width and diver- 

 gent across the epistoma. Subepistomal area moder- 

 ately large, concave and oblique. The face is minutely 

 micropubescent, the middle of the gibbosity doi-sally 

 bears a dense tuft of moderately long, stiff pile; this 

 pile is continued more scantily down the sides of the 

 epistomal margins. The whole anterior and lateral 

 epistomal margins bear a circlet of 7 pairs of long, very 

 stout, black bristles, the lower 3 elements shorter and 

 weaker. The front is short, bare medially, with a 

 dense tuft or band of long, bristly pile along the eye 

 margin; vertex deeply excavated with nearly vertical 

 sides, more deeply excavated behind. The ocellarium is 

 rather low, with 2 pairs of slender, black bristles across 

 the middle and 2 pairs between the posterior ocelli, 3 

 pairs immediately behind and 4 or 5 pairs set further 

 clown along the medial ridge. Anterior eye facets mod- 

 erately enlarged. 



Thorax: The thorax is pollinose, abrupt both an- 

 teriorly and posteriorly. The pile of the mesonotum is 

 dense, but quite fine, rather short, bristly and suberect, 

 a little longer anteriorly and still longer posteriorly. 

 Acrostical bristles not differentiated ; dorsocentral bris- 

 tles are present only opposite the postalar, where there 

 is a row of 8 or 9 elements followed by a medial, more 

 posterior row of 4 or 5 elements, all rather long and 

 stout. Humerus with fine, short, bristly pile. In the 

 type of genus the lateral bristles are stout and long, and 

 consist of 2 notoplem-al, 1 postsupi'aalar, 3 postalar, 

 and 3 pairs of slender scutellar bristles, with 3 or 4 ad- 

 ditional, equally stout bristles on each side of the disc. 

 Scutellum thick and convex, without trace of impressed 

 rim. Propleuron densely long, fine, pilose with only 

 bristles on the pronotum where there are 4 or 5 pairs of 

 weak bristles. Anterior and upper mesopleuron, the 

 whole upper posterior half of the sternopleuron with 

 mostly long pile. Pteropleuron with a dense clump of 

 long, fine pile ; posthypopleuron likewise ; metapleuron 

 with a wide, vertical band of long, slender bristles and 

 bristly pile ; lateral slopes of metanotum micropubescent 

 only; lateral and ventral metasternum long, fine pilose; 

 postmetacoxal area membranous ; tegula with setae, an- 

 terior basalare with a tuft of 12 or more long, fine hairs. 

 Prosternum dissociated. 



Legs : The femora are stout, the middle and anterior 

 pairs distinctly thickened towards the base. Dorsal, 



