558 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



In the genus Neoitamibs, Beling (1882) and Melin 

 (1923) treat the immature stages of Neoitamus cyanu- 

 rus and sockis. According to Irwin-Smith (1923) sev- 

 eral authors have treated the immature stages of Asilus 

 aestivus, which probably rejiresents Neoitamus 

 cothurnatus. 



Genus Erax Scopoli 

 FiGUBES 302, 793, 1495, 1504, 2222, 2234, 2284, 23T4 



Erax Scopoli, Entomologica carniolica . . ., p. 359, 1763. Type 



of genus: Erax hariatus Scopoli, 1763. Designated by 



Coquillett, 1910, the fifth of 14 species. 

 Protophancs Loew, Abh. Naturw. Ver. HaUe, Berlin, vol. 2, p. 



143, 1860. Type of genus : Asilns punctatus Meigen, 1804. 



Designated by Bngel, 1926, the first of 3 species. 



Medium size, rather long pilose, bristly flies with a 

 robust appearance in the males due to the large, broad, 

 clublike terminalia but with the females rather strongly 

 attenuate. The abdomens in both sexes sometimes a 

 little compressed laterally but more or less subcylin- 

 drical. The face is pi'ominent, distinctly abrupt be- 

 neath the antenna and bears long, numerous, slender 

 bristles. The rather long, third antennal segment is 

 exceptionally slender. Length 15 to 20 mm. 



Head, lateral aspect: The face is imusually prom- 

 inent, narrowed laterally and convex anteriorly; it is 

 very abrupt dorsally and for a short distance beneath 

 the antenna reduced to eye level. Eye narrowed some- 

 what below the middle, long, flattened anteriorly and 

 rather strongly recessive anteroventrally on the lower 

 third of the posterior portion. The occiput is rather 

 thick medially throughout, more prominent above the 

 middle ; pile of the occiput dense, rather long and fine 

 and matted ventrally, shorter in the middle but again 

 extremely long vertically. On the upper fourth are 

 about 5 pairs of weak, slender bristles. The proboscis 

 is short, and rather slender, slightly tapered to a 

 rounded point, bearing numerous bristly hairs on all 

 sides of the apex and with a ventrolateral fringe of 

 numerous, long, fine hairs on the basal half; a dorsal 

 ridge is absent; it is directed chiefly forward. Palpus 

 rather long, moderately stout, cylindrical, with fine 

 bristly hairs at the apex. The antenna is attached a 

 little below the upper third of the head, of usual length, 

 but unusually slender; the first segment is IV^ times as 

 long as the second, which is considerably widened dis- 

 tally. The third segment is distinctly more narrow than 

 the second, nearly li^ times as long as the first two com- 

 bined, and continues to be quite slender throughout ; it 

 is a little narrowed distally and bears a very short, 

 microsegment, followed by an attenuate style half as 

 long as the third segment, with apical bristle. First 

 antennal segment with numerous, rather fine, pale, 

 bristly hairs on all sides except medially ; apex of sec- 

 ond segment with similar but shorter pile. 



Head, anterior aspect: The face below the antenna 

 is a third the head width, considerably wider at the 



epistoma. Subepistomal area moderately large, oblique, 

 concave, pubescent. The face is quite prominent, the 

 sides flattened, the whole strongly convex and gibbous, 

 and rising abruptly a short distance beneath the an- 

 tenna ; the face immediately below the antenna is plane 

 with the eye, the antenna attached to a low prominence. 

 The face is apilose, with numerous, quite long, curved, 

 slender bristles of nearly uniform tliickness throughout. 

 These begin at the base of the gibbosity dorsally and 

 extend down over the upper half of the lateral sub- 

 epistomal margins; they are nearly as long as the an- 

 tenna and below extend well beyond the proboscis. 

 Front with a dense, lateral tuft of numerous, quite long, 

 slender, bristly hairs or weak bristles; vertex mod- 

 erately excavated, the sides steep, the ocellarium large 

 with prominent ocelli and bearing across the middle 

 4 or 5 pairs of slender, bristly hairs with as many others 

 behind the ocelli. Anterior eye facets a little enlarged. 



Thorax: The thorax is pollinose; the mesonotum is 

 abrupt and vertical anteriorly and more than usually 

 convex posteriorly. Pile of mesonotum abundant, im- 

 usually long, fine and bristly, with a narrowly differen- 

 tiated band of acrostical pile and with long, slender, 

 dorsocentral elements on the anterior half which become 

 extremely long and somewhat stouter posteriorly and 

 consist of 8 to 10 pairs behind the suture. Humerus 

 with only fine, erect, short pile. Lateral bristles very 

 stout and consist of 3 notopleural, besides 2 slender, 

 posthvmieral, 3 supraalar, 2 postalar with 5 more addi- 

 tional, slender elements and 5 pairs of exceptionally 

 long scutellar bristles. Scutelhim thick and convex, 

 with distinct impressed rim, pubescent and with abun- 

 dant, long, fiine pile. Propleuron densely long, fine 

 pilose; the pronotum without bristles, the posterolateral 

 pronotmn also with only fine pile. The anterior sterno- 

 pleuron, the postdorsal sternopleuron, the pteropleuron, 

 each with a tuft of fine, long hairs. Mesopleuron dor- 

 sally with a double row of 5 slender, bristly hairs ; post- 

 hypopleuron with 1 stout, 3 or 4 slender bristles and 

 several, bristly hairs. Metapleuron with a double, ver- 

 tical row containing 6 or 7 exceptionally straight, stout 

 bristles and with additional bristly hairs. Lateral 

 slopes of the metanotum with a dense patch of bristly 

 pile; ventral metasternimi with abundant, long pile. 

 Postmetacoxal area membranous; tegula with minute 

 setae, posterior basalare with 4 or 5 slender hairs ven- 

 trally ; anterior basalare pubescent only ; squama with a 

 multiple fringe. 



Legs: The femora are only moderately stout, the 

 hind femur least stout, the anterior femur slightly 

 thickened towards the base. The hind tibia is slightly 

 shorter than its femur. Hind femur and to a lesser 

 extent the others with rather scanty, fine, appressed 

 pile, a little longer and less appressed laterally; the 

 ventral surface bears a few, fine, suberect hairs and an 

 abimdant, ventral, medial fringe of long, fine pile. 

 Hind tibia ventrally only with short., fine subappressed 

 pile and a medial brush of setae beginning at the base. 



