550 



tJNITED STATES NATIONAL MUSEUM BULLETIN 224 



ment and an unusually short, stout style half as long 

 as the third segment; style with apical spine. The first 

 segment has numerous, short, stout setae, especially be- 

 low; second segment with a few setae apically above 

 and below. 



Head, anterior aspects : The face below the antenna 

 is a fourth of head width and slightly divergent below. 

 The subepistomal area is large, oblique, plane and 

 pubescent. Face pubescent, the pile and bristles re- 

 stricted to a large, triangular area on the middle and 

 lower three-fifths of face ; the middle bears stiff, bristly 

 pile, the lower marginal area has rather longer, nu- 

 merous, slender bristles. Front moderately divergent, 

 the vertex slightly convergent. Sides of front with 

 numerous, slender, bristly hairs; vertex moderately 

 excavated with gently sloping sides; the ocellarimn 

 is low, bearing 6 to 8 pairs of stiff hairs. Anterior 

 facets slightly enlarged. 



Thorax: The mesonotum and pleuron pollinose; 

 mesonotum more or less uniformly covered with nu- 

 merous, fine, short, subappressed setae ; the sides, includ- 

 ing the humerus, bear longer, coarse pile. Acrostical 

 elements not differentiated; dorsolateral elements 

 equally short but near the middle they become slightly 

 longer and posteriorly fomi about 4 or more long, stout 

 bristles. Lateral margins with long, stout bristles con- 

 sisting of 2 notopleural, 2 supraalar, and 3 postalar; 

 the scutellum with 3 pairs of marginal bristles. Scutel- 

 lum thick, convex, pollinose with impressed rim and 

 nimierous, long, stiff hairs on the disc. Propleuron 

 with abundant, long pile; pronotiun with stiff, bristly 

 hairs. Mesopleuron dorsally and posteriorly with only 

 a few, scattered, stiff hairs but the anterior prolonga- 

 tion, the upper sternopleuron, and the central ptero- 

 pleuron with a dense patch of long, stiff pile. Posthy- 

 popleuron with 2 or more distinct, long bristles. 

 Metapleuron with 5 to 10 long, slender bristles; meta- 

 notal slopes with a large, dense patch of stiff pile or 

 weak bristles. Lateral and ventral metastenium with 

 long pile; postmetacoxal area membranous; j^osterior 

 basalare with a few weak setae ; squama with a multiple 

 fringe. Prosternum united to the lateral propleuron 

 by a narrow strip of chitin. 



Legs: All the femora are stout; the anterior femur 

 is distinctly thickened towards the base. The hind 

 femur is thick, with long, appressed setae dorsally, lat- 

 erally, and ventrally, and also with a few long, scat- 

 tered hairs ventrally and medially; it bears the follow- 

 ing short, stout bristles: 1 medial at apex, 1 dorsome- 

 dial subapical and 8 dorsolateral, 5 or 6 ventrolateral, 



3 ventral at the base and 1 beyond the middle. This 

 tibia bears 1 long dorsal in the middle, and 4 lateral and 



4 ventrolateral beginning at the middle ; apex with 9 or 

 10 bristles. Middle femur with 1 long, stout, anterior 

 bristle at the apical third, 1 at basal third and 3 or 4 

 short ventral bristles and long, stiff pile behind; middle 

 tibia with 2 dorsal and 2 posterodorsal elements beyond 

 the middle, 4 posterior and 2 long ventral bristles. An- 

 terior femur with only a prominent, ventral fringe of 



long, stiff pile; its tibia has 3 short, dorsal elements 

 on the basal fourth and 5 posterodorsal elements beyond 

 the middle, besides 2 long, straight, oblique, ventral 

 bristles at the middle and apically. Apical circlet with 

 10 bristles ; the medioventral element and the one above 

 it are each nearly as long as the basitarsus and the base 

 of the basitarsus and its apex have equally long, stout 

 bristles. The dorsal apex of the first tarsal segment, 

 the second segment apically and the second and third 

 ventrally, each with 2 long, stout bristles, longer than 

 the segment itself. Tarsi end in well developed 

 pulvilli; long empodiimi; long, sharp, apically bent 

 claws. 



Wings : The marginal cell is closed with a short stalk ; 

 the anterior branch of the third vein ends above the 

 wing apex; posterior branch ends an equal distance 

 below the apex. The first posterior cell is slightly nar- 

 rowed in the middle ; second posterior cell slightly swol- 

 len basally; lower end vein of the discal cell pulled 

 back; fourth posterior cell closed and stalked. The 

 discal cell is only slightly narrowed in the middle ; anal 

 cell closed, second basal cell ends in 2 veins which are 

 fiised beyond. Alula large; the ambient vein ends at 

 the anal cell. 



Abdomen: The abdomen is cylindroid and tapered, 

 the first tergite is swollen and convex laterally and the 

 abdomen is a little longer than the wings. Pile of abdo- 

 men quite flat appressed, fine and setate, somewhat 

 longer and more erect on the sides of the first tliree ter- 

 gites; sternal pile is scanty, fine and long on the first 

 three segments, appressed, short setate on the re- 

 mainder. Bristles are restricted to first tergite, with 

 5 to 7 present. Eight tergites are present in the male, 

 the eighth however, very narrow and linear; seven 

 tergites in the female exclusive of ovipositor. Male 

 terminalia moderately large and conspicuous and not 

 rotate. Superior forceps slender, elongate and directed 

 straight backward. The gonopod is about half as long 

 as the upper forceps and is arched upward. Proctiger 

 promiiient, protruded and erect. Hypandrium short 

 and transverse; genital cavity widely open. These 

 terminalia are veiy similar to those of Asilus, sensu 

 stricto. 



The female terminalia consist of the moderately long 

 eighth segment of which the tergite is nearly cylindrical 

 and the sternite a little pinched and compressed ; they 

 bear rather abundant, quite erect, stiff pile, also sug- 

 gestive of Asilus. The ninth tergite is elongate, convex 

 on top, slightly longer than the tenth segment ; and the 

 eighth steniite below extends forward below through its 

 full length. Last segment densely covered with very 

 minute, erect, bristly hairs. Eighth segment a little 

 longer than the seventh. 



Distribution: Nearctic: Antiphrisson astutus Wil- 

 liston (1893). 



Palaearctic: Antiphrisson adpressus Loew (1849), 

 adpressus candidus Villeneuve (1924) ; angustifrons 

 Loew (1849) ; elachypferyx Loew (1871) ; fuligineus 

 Loew (1871) ; «are;?tem« Lichtwardt (1903) ; thalham- 

 meri Lichtwardt (1903) ; trifarius Loew (1849). 



