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UNITED STATES NATIONAL MUSEUM BULLETIN 224 



lei sides and not quite as wide as the mesonotiun and 

 tapered on the end of the fifth segment. The fii'st ter- 

 gite is laterally swollen. Pile of abdomen fine, abun- 

 dant and flat appressed ; it is somewhat longer and erect 

 but scanty on the sternites. The bristles present are ex- 

 tremely weak and slender: 4 or 5 bristles on the first 

 tergite and along the posterior margin of the third and 

 fourth tergites submedially there are 3 or 4 paire of 

 long, slender, appressed bristles. There are seven ter- 

 gites in the male, the eighth quite concealed. Females 

 with seven tergites, the eighth distinctly incorporated 

 in the ovipositor. The male terminalia comparatively 

 small but only moderately elongate. The superior for- 

 ceps are separated even at base with simple, slightly 

 narrowed apex which comes to the midline; the proc- 

 tiger is long, proti-uded and erect. The gonopod is 

 more than half as long as the upper forceps with short 

 but sharp apical process and both these structures are 

 directed straight backward. The hypandrium is short 

 and transverse. The genital cavity is open but greatly 

 narrowed. Female terminalia short and conical, 

 slightly compressed laterally. 



Distribution: Neotropical: Anannostus ioptenis 

 Wiedemann (1828). 



Genus Asilus Linne 

 FiGUEES 380, 765, 1622, 1629, 2290, 2316, 2461, 2465 



AsiluB Linn^, Systema naturae, ed. 10, pp. 605, 227, 1758. Type 

 of genus : Asilus crabroniformis Linn6, 1758. Designated 

 by Latreille, 1810, the third of 12 species. 



Mediimi size to large flies with elongate, tapered 

 abdomen and a prominent, bristle-covered gibbosity on 

 the lower face. On the abdomen bristles are character- 

 istically restricted to the first tergite but may be rarely 

 present on the second tergite. Species with bristles be- 

 yond the second tergite fall into other genera. The 

 ovipositor is cylindroid and conical. On the wing the 

 anterior branch of the third vein ends shortly before 

 the apex of the wing and the posterior branch shortly 

 behind the apex. The base of the second posterior cell 

 tends to be abruptly and conspicuously widened in 

 comparison with the end of the discal cell ; the metano- 

 tal callosity is densely pilose or bristly. Length 16 to 

 28 mm. 



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

 the face moderately developed on the upper half and 

 sometimes concave, with on the lower half of face a 

 rather prominent gibbosity or extension which is de- 

 veloped gi-adually. The occiput is tliick, prominent 

 throughout and especially prominent below due to the 

 posterior ventral recession of the eye on the lower third 

 of the eye. It has numerous bristles, beginning at the 

 middle of the head and becoming more stout at the ver- 

 tex ; lowest elements are in a single row, the upper ele- 

 ments clustered. The proboscis is long, stout and ro- 

 bust basally, nearly plane or slightly concave on the 

 lower surface; it is rather strongly attenuate and 

 pointed on the apical fifth and the dorsal surface is 



slightly arched. The apex bears bristly pile both above 

 and below and long, bristly hairs ventrolaterally on the 

 basal half; proboscis generally directed forward. 

 Palpus of one segment, conspicuous, and robust with a 

 trace of the basal segment. The antenna is attached at 

 the upper third of the head and comparatively elongate, 

 especially on the third segment. The first and second 

 segments are long with the second a little shorter than 

 the first; the first segment bears numerous, stiff bristles, 

 appressed on the ventral and lateral surfaces and a few 

 dorsal bristles at the subapex. The third antemial seg- 

 ment is as long or slightly longer than the first two seg- 

 ments combined; it is widest near the base and atten- 

 uate with a distinct microsegment and the style is as 

 long as, or somewhat shorter than the third segment. 



Head, anterior aspect : The head is of moderate width, 

 less wide than the mesonotum. The face below the an- 

 temia is approximately a fourth the head width, rather 

 strongly divergent below. The cheeks are extensive 

 and, together with the face, pubescent. Pile is absent 

 on the upper half of tlie face in the type of genus and 

 the gibbous portion is densely beset with quite stout, 

 long bristles which extend down the sides of the large, 

 oblique, subepistomal area. Front pollinose with a sub- 

 ocular and an anterolateral row of stout bristles. The 

 front is wider tlian the upper face, and the vertex is 

 slightly narrowed, moderately excavated, with a rather 

 large ocellarium which bears 3 pairs of bristles between 

 the ocelli and 1 pair behind the ocelli ; all ocelli large. 



Thorax: The mesonotum is moderately high, com- 

 paratively long and only slightly convex, except near 

 the scutellum and anteriorly. Surface of mesonotum 

 pollinose, rather densely covered with short, stiff, sub- 

 appressed setae, undifferentiated anteriorly but with 

 prominent dorsocentral bristles beginning at the an- 

 terior plane of the postalar. There are usually 4 to 6 

 pairs of such long, postdorsocentral bristles. Humerus 

 with bristly pile, the lateral complement of long, stout 

 bristles consists of 2 notopleural with sometimes weak, 

 posthumeral bristles, 1 supraalar, 1 or 2 suprapostalar, 

 3 or 4 postalar and 2 to 5 pairs of scutellar bristles. 

 The scutellum is moderately thick with distinctly im- 

 pressed rim and numerous, erect setae or bristly hairs. 

 Pronotum with 5 or 6 pairs of bristles. The upper 

 margin of mesopleuron and its posterior margin like- 

 wise with bristly hairs. Upper pteropleuron with dis- 

 tinct, stout bristles and some hairs. Posthypopleuron 

 with at least 1 stout bristle, the metapleuron with a 

 vertical row of 5 stout bristles and some more slender 

 elements. Upper sternopleuron with numerous, long, 

 stiff hairs and others along the posteroventral margin. 

 Metanotal callosity densely covered with bristles and 

 pile. Prosterniun narrowly connected anterolaterally 

 with the lateral propleuron. Anterior basalare with 

 pollen only ; posterior basalare with a few, fine hairs ; 

 tegula with setae. 



Legs : The femora are quite stout, only the first four 

 a little swollen and all of them moderately elongate. 

 The pile is abundant, subappressed and setate, without 

 conspicuous fringes of long pile on either femora or 



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