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UNITED STATES NATIONAL MUSEUM BULLETIN 224 



slender bristles. Anterior eye facets enlarged over a 

 small area. 



Thorax : The thorax is either pollinose or with the 

 pleuron almost wholly shining. The pile of the meso- 

 notum is abundant, long and fine, and for the most 

 part bristly. The acrostical pile is poorly differentiated 

 in the type of genus on the anterior portion of the 

 mesonotum, but in some species there is a dense, very 

 long, thick mane beginning anteriorly and extending 

 throughout the length of the mesonotum and in other 

 species is confined to the posterior half of the mesono- 

 tum. There is a row of extremely long, but very fine 

 dorsocentral elements on either side containing 12 to 15 

 elements. Humerus with a few fine, long hairs. In the 

 type of genus the following complement of stout, long, 

 lateral bristles is present : 3 notopleural, 3 supraalar, 5 

 postalar, the scutellum with 8 to 10 pairs of long 

 bristles, besides additional long, fine, bristly pile on the 

 convex disc. Propleuron with long, densely matted, 

 fine pile over the whole; bristles absent, including the 

 collar. Upper mesopleuron and upper middle of the 

 sternopleuron with a tuft of long, fine pile; posterior 

 hypopleuron with a patch of slender bristles. Meta- 

 pleuron with a wide band of exceptionally abundant, 

 long, bristly pile. Lateral slopes of the metanotum 

 micropubescent only; the lateral metasternum has 

 short, fine pile; the chitinized ventral metasternum 

 is without pile. Postmetacoxal area membranous; teg- 

 ula with setae. 



Legs: The femora are quite stout without being 

 swollen and are relatively short. The pile is abundant, 

 long and rather matted, more or less appressed dorsally 

 on the hind femur and forming long fringes laterally 

 and posteriorly on the femur and tibia but especially 

 long and conspicuous on the tibia. In the type of genus 

 the following exceptionally long, stout bristles are 

 present : on the hind femur 6 lateral, a row of 4 close-set 

 dorsolateral on the outer fifth, 3 similar dorsomedial, 

 also 6 ventrolateral bristles. On the hind tibia are 5 

 dorsomedial, 4 dorsal, 4 dorsolateral, and set on the 

 outer half 2 lateral bristles; in addition the ventral, an- 

 terior, and posterior mats of long pile are very dense. 

 Middle femur with a prominent, matted fringe of long 

 pile on the anterior, dorsal, and posterior surfaces and 

 several long, stout, anterior bristles. These tibiae have 

 6 very long, attenuate, stout, anterodorsal bristles, 5 

 similar dorsal, at least 4 posterodorsal, and 5 posterior 

 bristles. The postero ventral area is occupied by a still 

 longer fringe of dense, opaque pile, the corresponding 

 anteroventral surface similarly covered. Anterior fe- 

 mur with long pile posteriorly and appressed, long pile 

 dorsally and anteriorly with 1 dorsal subapical and 2 

 posterosubapical bristles; anterior tibia with 7 ante- 

 rodorsal, at least 6 posterodorsal, 5 posteroventral 

 bristles intermixed with long pile, 4 or 5 long ventral 

 bristles with long pile. Apex of anterior tibia without 

 spine. Bristles of the tarsi exceptionally long, longest 

 posteriorly on the middle tarsi; all tarsi end in long, 

 sharp, gently curved claws without pulvilli ; empodium 

 long and moderately compressed laterally. 



Wings : The marginal and all of the posterior cells 

 widely open : the second basal cell ends in three veins, 

 the middle vein short. Anal cell open. Alula a little 

 wider than the costal cell ; ambient vein complete. 



Abdomen: The abdomen is short, robust, convex 

 above but distinctly compressed laterally. Male with 

 seven tergites; the seventh is one-third as long as the 

 sixth segment; sixth tergite slightly shorter than the 

 fifth. Females with eight tergites. Sides of the first 

 tergite with 3 or 4 pairs of long, bristly hairs, other- 

 wise bristles are absent. Pile of abdomen dense, very 

 long, fine and rather matted; sternites with similar 

 pile. Male terminalia of moderate length, not rotate, 

 the superior forceps short. The females bear acantho- 

 phorites with a series of short dorsolateral spines. 



Distribution: Palaearctic: Anarolius fronto Loew 

 (1873) ; jubatus Loew (1844). 



Genus Pycnopogon Loew 



Figures 108. 499, 1011, 1012 



Pycnopogon Loew, Linnaea Entomologiea, vol. 2, p. 526, 1847. 

 Type of genus: Pycnopogon mixtus Loew, 1847, by 

 monotypy. 



Medium size flies of robust character. Distinguished 

 by the extremely long, shaggy pile of the thorax, head, 

 legs and the sides of the abdomen. Related to Hetero- 

 pogon Loew, they are separated by the wider vertex 

 and wider ventral part of face; these parts are dis- 

 tinctly wider than the face immediately below the 

 antenna. The antenna usually slender with two micro- 

 segments, the second microsegment quite long and at- 

 tenuate. Length 10 to 17 mm. 



Head, lateral aspect: Face rather short, slightly 

 convex, the eyes of medium length, well developed 

 above and below, strongly convex anteriorly, gently 

 convex behind. The occiput is short but better devel- 

 oped ventrally, especially towards the medial area. 

 The pile of the occiput is dense, matted and long, 

 with 10 pairs of bristles on the dorsal third, which are 

 obscured by pile. The proboscis is short, stout, obtuse- 

 ly pointed and tapered chiefly on the dorsal apical 

 aspect. From the dorsal view it is rather strongly 

 widened towards the base; the apex bears a few long, 

 stiff hairs above and below, and there are numerous 

 long hairs laterally at the base. Palpus clearly of 

 two segments, the first excavated, the second cylindri- 

 cal, not porate, with numerous, long bristly hairs on 

 the apex and on all sides except the medial. The an- 

 tenna is attached at the upper fourth of head; it is 

 rather long and slender and distinctly longer than the 

 head. The first segment is a little longer than the 

 second, the third, including the style, nearly twice as 

 long as the first two. The third segment is widest at 

 the base, more slender than the preceding segment, 

 strongly attenuate, obliquely truncate at the apex and 

 carries two microsegments held at a strong, oblique, 

 ventral angle downward, the first short, the second at- 

 tentuate to a point and carrying a short spine. First 



