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UNITED STATES NATIONAL MUSEUM BXTLLETIN 224 



outer sixth; the outer members form part of a dorso- 

 lateral row of 5 bristles. Ventrolaterally, near the base 

 there are 3 weak, short bristles. There are 3 long, ven- 

 tral bristles at the middle and before it, and a medial, 

 appressed row of 10 or 12 bristles. The hind tibia bears 



2 strong, dorsomedial, 2 dorsolateral and 2 ventrolateral 

 bristles, all distributed along the middle third. In 

 addition, near the base lies a pair of dorsal bristles 

 which should be included in these rows, and there are 



3 ventral elements, increasing in length. Apex with 1 

 dorsal, 2 lateral, 3 long and 2 quite short ventral bristles. 

 Hind basitarsus rather slender and elongate and nearly 

 as long as the remaining segments together ; second to 

 fourth segments equal in length. Middle femur with 1 

 stout posteroapical, 1 weak anteroapical, 1 stout an- 

 terior at the outer third, 3 short anteroventral and 5 

 posteroventral bristles. The middle tibia bears 2 stout 

 dorsal on the outer half, 2 similar anterior, 3 posterior, 

 2 posteroventral, 1 at the outer third especially long 

 and stout and with 2 ventral bristles of sunilar charac- 

 ter. 



The anterior femur cliaracterized by 3 relatively 

 stout, posterior bristles on the outer half, the last one 

 only is subapical, and short, stout, anteroapical bristles 

 and 5 more fine, long, stiff hairs below. The anterior 

 tibia has 3 anterodorsal, the basal element longer and 

 stouter, 2 stout, central doi-sal, preceded by 2 weak ele- 

 ments and followed by 1 weak bristle and 3 rather long, 

 stout, posterior bristles. The apical circlet has 12 

 bristles. Posteroapical bristles of the tarsal segment 

 especially long and stout ; tarsi with large, nearly rec- 

 tangular, long pulvilli, long, basically stout empodium, 

 sharp claws bent chiefly at the apex. 



Wings: The wings are hyaline or slightly tinged and 

 anteriorly rippled but the costa and marginal cells not 

 expanded and the wing not wider basally. The mar- 

 ginal cell is closed with a short stalk; the anterior 

 branch of the third vein ends slightly but distinctly 

 above the apex. The second submarginal cell is scarcely 

 narrowed in the middle and tlie second posterior cell 

 only a little widened basally; fourth posterior cell 

 closed and stalked, slightly but distinctly convex an- 

 teriorly ; anal cell closed and stalked ; second basal cell 

 ends in two veins; alula large, ambient vein complete. 



Abdomen: The abdomen is distinctly narrower than 

 the mesonotum, slightly tapered and cylindrical and 

 as long as the wings. The pile is abundant but flat 

 appressed and setate, only the sides of the first two 

 tergites bear long, fine, erect, lateral pile; the third 

 tergite has a very few, erect hairs laterally. Sternites, 

 except the last three, bear long, erect pile. Bristles are 

 present on all the tergites but weak on the last three. 

 The first tergite has 2 stout, long bristles and stitf , long 

 pile. Second, third and fourth tergites with especially 

 prominent, long, stout, nearly erect bristles. Male 

 with eight tergites, the eighth is quite short and about 

 a fifth as long as the preceding tergite. Male termi- 

 nalia large, elongate, extended posteriorly, not rotate. 

 The superior forceps elongate and slender, the apex of 

 each half tends to curve to the midline, leaving a char- 



acteristic, enclosed, open space beyond the gonopod. 

 Gonopod about half as long as the upper forceps; 

 hypandrium well developed, with transverse margin. 

 Aedeagus with three prongs, but retained within the 

 ventrally open cavity. Proctiger prominent, pro- 

 truded but oblique. The female terminalia consist of 

 the eighth segment, which is about as long as the sev- 

 enth, is polished and shining and posteriorly com- 

 pressed laterally. The sternite is also compressed and 

 extends below the ninth tergite. Ninth tergite a little 

 longer than the tenth. At the apex the tenth tergite 

 characteristically beai-s on each side 4 sharp spines of 

 decreasing size, the largest element dorsal. 



Distribution: Nearctic: Philonicus arlzonensis Wil- 

 liston (1893) ; /t<sc(Zi!M.9 Hine (1909) [ = o&scm7^s Hine 

 (1907) not Meigen] ; Umpidipennis Hine (1909) ; rufi- 

 pennis Hme (1907). 



Neotropical: Philonicus tuxpanganus Bellardi 

 (1862). 



Palaearctic. Philonicus alMceps Meigen (1820) 

 [ = alh{barhus Zeller (1840), canescens Wiedemann in 

 Meigen (1820), niarinus Becker (1923), nudus Loew 

 (1840), pulcher Becker (1923)]; domesticus Eicardo 

 (1920) ; dorsiger Wiedemann (1828) ; elutus Loew 

 (1871) ; scau7nis Walker (1849) ; sinaiticus Efflatoun 

 (1934). 



Oriental: Philonicus nigrosetosus Wulp (1881). 



Australian: Philo7iicus longulus Wulp (1872). 



Country unknown: Philonicus vagans Wiedemann 

 (1828). 



The immature stages of Philonicus albiceps have 

 been described and illustrated by Melin (1923). 



Verrall (1909) assigned Asilus delector Harris 

 (1782), to synonymy under Philonicus alhiceps. 



Genus Machimus Loew 



FiQUEES 332, 775, 1533, 1542, 2308, 2331, 2492, 2496 

 Machimus Loew, Linnaea Entomologica, vol. 4, p. 1, 1849. Type 

 of genus: Asilus chrysitis Meigen, 1820. Designated by 

 Coquillett, 1910, the second of 15 species. 



Machimus has one subgenus, Conosiphon Becker. 



Medimn size to large flies, characterized by the prom- 

 inent gibbosity of the face, wliich is densely covered 

 with bi'istles. There are stout, postlateral bristles on 

 most tergites. The terminal proctiger of the female is 

 free. The apical lobelike or lappetlike extension of 

 the male eighth sternite is shared by Eutolmus Loew 

 but is rounded at the apex in Machimus and tends to be 

 excised in Eutolmus. In addition, tlie thick, scutellar 

 disc is long, bristly pilose and the aedeagus has 5 

 prongs. Sternites witli a few bristles. Length 12 to 30 

 mm. 



Head, lateral aspect : The head is of medium length, 

 the face quite prominent except upon the upper fourth 

 beneath the antenna, where it is nearly plane with the 

 eye. The occiput is well developed throughout, more 

 prominent on the ventral fourth due to the distinct 

 posteroventral recession of the eye. The proboscis has 

 a rounded apex ; the apex distally has numerous, long, 



