510 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



with a long, basal petiole. Anal cell closed with a 

 stalk. Posterior branch of the third vein ends distinctly 

 behind the apex of the wing. The anterior branch ends 

 slightly in front of the apex. 



Abdomen : The abdomen is black in ground color on 

 the first segment and on most of the second and third 

 tergites, becoming very dark, brownish black across the 

 middle of the remaining tergites and with the side mar- 

 gins of all the tergites light, reddish brown. Posterior 

 margin of all the tergites witli a pale, yellowish grey, 

 extensively poUinose, marginal band. The anterior por- 

 tion of each tergite has, in some lights, a brownish, yel- 

 low pollen bearing numerous, small flecks or spots of 

 darker color. Pile scanty, appressed, fine, chiefly yellow 

 and setate. The last tei'gite is rather short and rather 

 light reddish brown ; it is a little longer laterally. Sides 

 of first tergite with 2 long, slender, white, bristly hairs 

 and a nmnber of other shorter, white hairs. Postero- 

 lateral portion of the remaining tergites each with 1 or 

 2 quite slender bristles, mostly pale. There are a very 

 few scattered, black setae near the middle of the 

 tergites. Male terminalia quite long and large, the super- 

 ior forceps elongate, strongly rounded laterally and 

 bluntly rounded at the apex. Hypandrium large and 

 triangular, the gonopod prominent, the whole ter- 

 minalia light reddish brown, paler at the end of the 

 gonopod. 



Female similar to the male. The tergal bristles 

 slightly more prominent, the tergites slightly more 

 blackish, the sternites, however, more reddish and also 

 with distinctly mottled or pebbled pollen. The female 

 terminalia are strongly compressed laterally but per- 

 haps properly only include the eighth and following 

 segments. The seventh segment is pollinose and like the 

 other tergites, although reduced to half its width pos- 

 teriorly ; the eighth tergite is at least as long as the sixth 

 and seventh combined, and maximally compressed at the 

 apex. Ninth and tenth tergites each rather long and 

 equally compressed, the tenth extending completely free 

 of the ninth sternite. 



Type : ]\Iale, allotype female, Concepcion, Chile, No- 

 vember 19, 1908, collected by P. Herbst. In the collec- 

 tions of the Deutsches Entomologisches Institut, Berlin. 



Genus Leptoharpacticus Lynch Arribalzaga 



FiGTJBES 373, 687, 1494, 1503, 23-16, 2359 



Leptoharpacticus Lynch Arribalzaga, Ann. Soc. Cient. Argen- 

 tina, vol. 10, p. 178, 1880. Type of genus: Asilus mucins 

 Walker, 1849, by original designation. 



Small, slender, tapered flies with the female ter- 

 minalia long and very strongly compressed until it is 

 leaf-thin. The face is virtually plane with the eye 

 on at least the upper two-thirds, the whole profile 

 almost plane and vertical, that portion which is visible 

 ventrally as a low triangular elevation is due to the 

 recession of the eye. They are dark colored, gi-eyish 

 yellow pollinose flies with a long, hind femur, which 

 is slightly swollen distally; bristles are few and for 



the most part rather weak. Lateral metanotal callosi- 

 ties micropubescent only. The scutallum is moderately 

 thick and convex with a distinct impressed rim. Length 

 12 mm. 



Head, lateral aspect : The face is exceptionally short, 

 plane, and nearly vertical, the exposed portion below 

 is due to the recession of the eye and is bluntly tri- 

 angular. There is a very slight, shallow depression 

 on the lower half. The occiput is of medium thickness 

 through the the entire posterior aspect, disappearing 

 only at the immediate vertex ; both eye and occiput are 

 gently recessive anteriorly near the bottom of the head ; 

 the pile moderately abundant, long and fine and with 

 only 5 pairs of weak, pale, straight bristles dorsally. 

 The proboscis is only moderately large, subcylindrical, 

 with a low, dorsomedial ridge and distinctly though 

 slightly tapered toward the base from a dorsal aspect; 

 the apex is blimtly pointed and tapered both above and 

 below, and bears only a few bristly hairs; the lateral 

 margins near the base have 2 or 3 long, slender hairs 

 which extend outward and the ventrolateral margin 

 on a little less than the basal half bears a fringe of 7 

 or 8 similar, yellow hairs. Palpus minute, cylindrical, 

 black, with a few long bristles below and 2 at the apex. 

 The antenna attached at the upper third of the head, 

 with the first segment li^ times as long as the second, 

 the second segment longer than wide. The third seg- 

 ment is as long as the first two combined and at its base 

 as wide as the second and rather strongly tapered 

 apically. It has a long, distinct microsegment which 

 is slender and a little more than twice as long as wide, 

 followed by a slender, bristle-tipped style. This style 

 and microsegment together are as long as the third 

 segment. First segment ventrolaterally with 5 or 6 

 comparatively long, stiff, bristly hairs, among them 1 

 stout bristle and all of them black. 



Head, anterior aspect : The face below the antenna is 

 a fifth the head width and wider at the epistoma. Pile 

 on the face is restricted to 5 or 6 comparatively short, 

 pale, bristly hairs on the lower third of the face. On 

 each side of the middle epistomal margin are 2 pairs 

 of moderately stout, pale yellow bristles which reach 

 to the end of the proboscis ; there are along the lateral 

 margins of the subepistoma 3 other equally long, more 

 slender bristles which represent a continuation of the 

 transver.se row ; and still lower on the epistomal margin 

 are 4 pairs of much shorter, more slender, pale bristles. 

 The fi'ont is quite short due to the deep excavation of 

 the occiput. Along the eye margins are 3 or 4 short, 

 rather stout, black bristles. Sides of the vertex not 

 quite vertical ; the ocellarium is set anteriorly and visi- 

 ble in profile though exceptionally low. It is however, 

 comparatively wide, nearly circular with nearly verti- 

 cal side; it is without pile or bristles. Anterior eye 

 facets only moderately large and convex. 



Thorax : The mesonotmn is rather high and strongly 

 convex anteriorly. The acrostical elements are absent ; 

 of dorsocentral elements there is a single pair poste- 

 riorly which are rather long and only moderately 



