ROBBER FLIES OF THE WORLD 



509 



long, ventral apical bristles. The anterior femur has a 

 prominent, moderately dense row of long, oblique, 

 dorsal bristles, the distal elements black and replaced 

 basally by 5 or 6 long, slender, yellow hairs. Ventral 

 margin of anterior femur with 10 or 12 long, yellowish 

 hairs and weak bristles. Anterior tibia with 5 long 

 dorsal, and 3 long, stout, black, posterior bristles but 

 with only stiff, yellow hairs ventrally. The apex bears 

 extremely long bristles, 2 anterior, 3 ventral, 2 dorsal, 

 1 posterior. Basitarsus rather short with veiy long, 

 posterior bristles. Claws long and sharp; pulvilli 

 nearly as long as claws; emj^odiuni nearly as long as 

 pulvilli and bladelike. 



Wings: The marginal cell is slightly widened and 

 rippled but the wing is not expanded ; this cell is closed 

 with a moderately long stalk. The second submarginal 

 cell takes origin just beyond the end of the discal cell 

 and at its base is equally expanded above and below ; 

 the anterior branch of the third veiii ends just above 

 the wing apex, the posterior branch a little farther be- 

 hind. The upper end vein of the discal cell is ex- 

 tremely short and almost eliminated, so that the end 

 of the discal cell is very narrow, but the base of the 

 second posterior cell is not narrowed except at its im- 

 mediate attachment to the discal cell. Fourth posterior 

 and anal cells closed with a short stalk ; anterior cross- 

 vein nearly rectangular; alula large, ambient vein 

 complete. 



Abdomen: The abdomen is cylindroid and rather 

 distinctly flattened on the middles of the firet five or 

 six tergites. First tergite about a third the length of 

 the second, moderately protruded laterally, with a 

 shallow crease and with a considerable amount of stiff, 

 yellow hairs and 2 or 3 weak bristles posteriorly and 

 sublaterally. The subposterior marginal area of the re- 

 maining tergites bears 1 or 2 short, yellow or black 

 bristles. Males with eight tergites, the eighth being 

 considerably shortened medially. Seven tergites are 

 present in the female. The ovipositor is a little longer 

 than the last two segments and strongly and gradually 

 compressed laterally. Male terminalia prominent and 

 not rotate. The superior forceps large, short, obtuse, 

 each half bent sharply inward at apex with a deep, 

 dorsal notch. The proctiger is not extended above. 

 The gonopod is half as long as the superior forceps; 

 the hypandrimn is prominent and large and the eighth 

 sternite is short with simple apex. 



Distribution: Neotropical: Myaptex hermanni, new 

 species. Named in honor of Friedrich Hermann. 



Myaptex hermanni, new species 



Length 11 mm. Male. Head: The head is black in 

 ground color, the face with pale, brownish white micro- 

 pubescence, extending over the cheeks, but less dense on 

 the gibbosity. The gibbosity has about 6 long, slender, 

 black bristles on each side in vertical rows and several 

 slightly shorter, more slender, white bristles. Sides of 

 subepistoma with 4 slender, black bristles and 2 or 3 

 white hairs. "Ventral surface of proboscis with con- 



spicuous, rather abundant, long, white, opaque pile and 

 lower half of occiput with similar, abundant, opaque, 

 white pile. Occiput along the middle of the eye with 7 

 or 8 slender, white bristles curved downward. Upper 

 occiput with more stout, short, black bristles, behind 

 which are some stiff, white hairs. The first two seg- 

 ments of the antenna brownish black, the third segment 

 black, short oval, as much narrowed at the base as at 

 the apex and the extreme base reddish. The short style 

 is black and only about as long as the third segment. 

 Pile of the first two antennal segments almost entirely 

 black with a few, pale hairs ventrally at the base of the 

 first segment. Front with quite long, slender, black, 

 bristly hairs and the low ocellarium with 5 still longer, 

 slender, black bristles on each side. Surface of front 

 with light brown pollen laterally. 



Thorax: The mesonotum is moderately high, black 

 with light brown pollen. From the anterior view there 

 is a wide, medial, sepia brown stripe obscurely divided 

 by linear pale brown pollen, and on either side of linear 

 stripe an acrostical row of moderately long, slender 

 bristles. Dorsocentral bristles not differentiated until 

 the posterior level or plane of the humerus. There are 

 5 rather long, dorsocentral bristles anterior to the su- 

 ture, 4 or 5 behind the suture, besides an additional 

 row posteriorly on each side lying between the dorso- 

 central bristles. All these bristles and those of the 

 lateral margin black. There are 2 notopleural, 1 supra- 

 alar, 1 suprapostalar, 1 postalar, and 1 pair of long, 

 slendei', scutellar bristles. Scutellum thick, convex, 

 without impressed rim, the micropubescent metanotum 

 lacks bristles or pile. Squamal fringe long and white 

 in 2 or 3 rows. Humerus pale brown pollinose with a 

 number of long, slender, bristly hairs or bristles. Disc 

 of scutellum with a few, fine, erect, stiff, black hairs. 

 Knob of halteres brownish black. The base reddish, 

 the stalk yellowish. Prosternum dissociated. 



Legs: The legs are comparatively slender, with the 

 anterior and middle femora a little swollen and with 

 the middle femur plane on the ventral aspect. Bristles 

 are numerous, moderately dense and long and especially 

 conspicuous on the tibiae and tarsi. All femora are 

 black, becoming reddish brown narrowly at the apex. 

 All tibiae and tarsi dark, reddish brown, including the 

 last segments. Claws quite slender, black, with the base 

 reddish. Pulvilli long and slender. Pile of the legs ap- 

 pressed and yellowish white ; all bristles black, with the 

 exception of 2 or 3 ventral bristles near the base on the 

 hind femur; a row of 10 or 11 bristles ventrally on the 

 middle femur and 2 or 3 bristles anteriorly and 1 pos- 

 teriorly on the same femur. On the anterior femur is a 

 ventral fringe of long, white, erect, bristly hairs with 

 still finer, long, bristly hairs on the anterior tibia. 



Wings : The wings are slender and nearly hyaline, at 

 least 31/2 times as long as wide. The second submarginal 

 cell is widened both above and below the third vein, the 

 subcostal cell is quite narrow, the discal cell is narrow, 

 with the medial crossvein more than 3 times as long as 

 the rectangular, upper, anterior, intercalary vein. 

 Fourth posterior cell closed with an oblique stalk and 



