200 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



der. All bristles and pile of the legs pale. Protibia 

 is without spine. Claws are fine, sharp; the pulvilli 

 long ; the empodium fine. 



Wings : The marginal cell is quite widely open. The 

 posterior branch of the third vein ends behind the wing 

 apex. First posterior cell is widely open, second pos- 

 terior cell absent. Fourth posterior cell is closed and 

 its stalk evanescent. The anal cell is similar. 



Abdomen: The abdomen is broad at the base and 

 nearly as wide as the mesonotum, comparatively short, 

 strongly convex from side to side dorsally. The abdo- 

 men is polished and bare for the most part with pale 

 pubescent bands, sometimes restricted to the first two 

 or three tergites and sometimes, where present, covering 

 the whole of the lateral margin, and more or less inter- 

 rupted medially. The pile is quite fine and scanty 

 except on the sides of the first tergite where there are 

 some long, slender bristles and long, coarse hairs and 

 also upon the terminalia where the long, coarse hairs, 

 though scattered, are much in evidence. Males with 

 seven tergites, the last only half as long as the sixth; 

 the females with eight tergites, the last also reduced 

 to half the length of the preceding segment. Male 

 terminalia exceptionally large, elongate, cuplike, the 

 appendages thin but wide and lengthened. The epan- 

 drium has become divided apparently into two very 

 widely separated halves, forming the superior forceps. 

 The intervening area, apart from the proctiger, is mem- 

 branous. Gonopod is most prominent ; the hypandrium 

 is a small, narrow piece closely set against the adjacent 

 gonopod and only half as long. The female has 

 acanthophorites, each with 3 or 4 long spines; ventral 

 plate divided apically and apposed, the terminal por- 

 tion pinched together and boatlike. 



Distribution : Nearctic : Itolia afripes Wilcox (1949) ; 

 maculata Wilcox (1936); tiiriberlakei Wilcox (1949). 



Genus Wilcoxia James 



Figures 82, 5S5, 971, 980 



Wilcoxia James, Journ. Kansas Ent. Soc, vol. 14, p. 38, 1941. 

 Type of genus : Wilcoxia cincrca James, 1941, by original 

 designation. 



Small, rather slender flies, pollinose, with short, in- 

 conspicuous, gently rounded face, long antennal micro- 

 segments. There is a stout, spinous bristle at the apex 

 of the middle tibia, somewhat turned backwards, and 

 no spine on the protibia. Length 6*4 to 9 mm. 



Head, anterior aspect: The head is short, the face 

 extremely short and not visible in profile beneath the 

 antenna, and only shortly visible along the middle and 

 below. It is gently curved and tends to follow the 

 eye margins to some extent. The vertex is prominent 

 in the middle and below due partly to the postero ventral 

 recession of the eye, which begins above the middle of 

 the head. The occipital pile is delicate and rather 

 abundant. There are 5 or 6 pairs of very weak, short 

 bristles above and a postvertical tuft of 3 on each side. 

 The proboscis is unusually stout basally and quite short, 



not extending beyond the face, its apex blunt. Palpus 

 small, of two segments, the first quite small and more 

 or less fused. The antenna is attached slightly above 

 the middle of the head; the first two segments short, 

 the second beadlike; the third is of nearly the same 

 width as the second for most of its length and slightly 

 tapered distally. It bears two microsegments ; the first 

 is small, the second rather long, of the same width, 

 slightly bent downward, and with a distinct spine at 

 the apex. First segment with a weak bristle ventrally, 

 second with 2 stronger bristles. 



Head, anterior aspect : Head is distinctly wider than 

 the thorax, the face narrow below the antenna, a little 

 less than a fifth of the head width, and rather strongly 

 divergent below. Face pubescent, with 5 or 6 fine hairs 

 on the upper half, and down the middle of the ventral 

 half 6 or more long, delicate, bristly hairs, sometimes 

 arranged in 3 transverse rows of 2 each. There are also 

 a few long, fine hairs above the epistoma and along 

 the subepistomal lateral margin; subepistoma moder- 

 ately large and oblique. Front, flat, pollinose, with 3 

 or 4 fine hairs laterally, its sides are almost parallel ; 

 the vertex is only moderately excavated, but the ocel- 

 larium is prominent with vertical sides, and bearing 

 several hairs and 2 or 3 bristly hairs, besides 3 addi- 

 tional pairs behind the ocelli. Anterior eye facets 

 rather strongly enlarged. 



Thorax : The mesonotum is rather convex and mod- 

 erately hump-backed, densely pollinose or micropubes- 

 cent with fine, scanty, reduced pile. There are a few 

 acrostical bristles present, 1 or 2 dorsocentral bristles 

 before the suture, and behind the suture 3 or 4 which 

 are longer. Humerus with a tuft of long, stiff hairs. 

 The lateral complement of bristles is 2 notopleural, 1 

 supraalar, 1 postalar, and 3 or 4 pairs of weak scutel- 

 lar bristles. Scutellum convex, pollinose, with a few 

 fine long hairs. Propleuron with some fine, long pile. 

 Metapleuron with a prominent, vertical band of long, 

 slender bristles; remainder of pleuron pollinose or pu- 

 bescent. Metanotum micropubescent only. Lateral and 

 ventral metasternum pilose, the postmetacoxal area 

 membranous. Presternum dissociated. 



Legs: The femora are rather slender, the anterior 

 pair a little thickened towards the base. They have 

 only appressed, scanty pile and long, bristly hairs. 

 The apex of the hind femur has 2 or 3 weak bristles 

 on each side dorsally. Some 4 or 5 of the exception- 

 ally long, ventral hairs on this femur might be con- 

 sidered weak bristles. Anterior femur with abundant, 

 long, fine pile posteriorly and ventrally. Middle fe- 

 mur with somewhat shorter, similar pile. Tibial pile 

 fine and subappressecl ; the bristles are mostly slender. 

 Hind tibia with 5 weak bristles dorsally, 2 on the outer 

 half are longer, with 2 well developed lateral and 2 

 similar ventrolateral bristles. Middle tibia with 5 

 anterodorsal bristles becoming progressively longer; 

 the last 2 are stout, with 3 or 4 posterodorsal, 6 pos- 

 teroventral and 3 prominent, long, stout, ventral 

 bristles. On the anterior tibia 3 or 4 short, postero- 

 dorsal bristles and 3 quite prominent, posteroventral 



