55-i 



tTSriTED STATES NATIONAL MUSEUM BXJLLETIN 224 



and gently taperod at the apex, laterally compressed 

 and beai-s a moderately long microsegment. The tliird 

 segment is 1^2 times the combined length of the first 2 

 seg:nents; it has a short miorosegment present and the 

 sliort style bearing an apical bristle is only a third the 

 length of the third segment. Pile of first segment com- 

 posed of dense, oblique, moderately long setae above, 

 below and laterally. Second segment with fewer, 

 shorter setae above and below. 



Head, anterior aspect : The head is only a little wider 

 than high. The face below the antemia is two-elevenths 

 the head width and double this width below. Subepis- 

 tomal area of moderate size, deeply concave and pubes- 

 cent. The face is pubescent and bears numerous, long, 

 stout bristles on the middle portion of the gibbosity 

 and the lateral margins of the epistonia. The upper ele- 

 ments are directed forward and curved, the othei-s 

 curved downward. The front is slightly divergent, the 

 vertex slightly convergent: sides of fi'ont convex and 

 bearing 6 or 7 weak bristles : vertex shallowly excavated 

 with slanting sides; ocellarimn large, with vertical 

 sides and bearing 3 or -i pairs of fine bristles. Eye 

 facets a little enlarged centrally. 



Thora:x: The mesonotimi is pollinose on a lateral 

 stripe and on the whole of the pleuron except a diag- 

 onal, bare stripe on the mesopleuron. Pile of meso- 

 notum exceptionally scanty, composed of fine, ap- 

 pressed. sharp setae; there is an acrostical row doubled 

 anteriorly but nearly absent through the middle of the 

 mesonotimi. At the notopleural level the doreocentral 

 elements become long and consist of 7 in each row. 

 Himierus with a few setae and a few long hairs. Lat- 

 eral bristles of the mesonotum exceptionally long and 

 stout : 5 notopleural. i supraalar, 1 suprapostalar, 5 

 postalar, and 3 pairs of scutellar bristles. Scutelhun 

 thick, convex, with impressed rim, pollinose and with 

 fine, erect setae on the disc. Propleuron with long, fine 

 pile and 5 pairs of stout bristles on the pronotimi. 

 Upper mesopleuron, posterior and anterior sections, the 

 upper ptein^pleuron, and sternopleuron each with a 

 patch of long, stifi" pile. Posthypopleuron with i espe- 

 cially long, moderately stout bristles ; meta pleuron with 

 a vertical row of 12 equally long bristles, i of them 

 stout. ^Metanotal slopes with 3 or 4 bristles and some 

 stilf pile. Metasternal slopes and the metasternum with 

 long pile; postmetacoxal area membranous; tegula 

 pubescent only but the posterior basalare bears a few 

 setae; squama with a multiple fringe. Prostemum 

 dissociated. 



Legs : AH the femora are stout ; anterior and middle 

 pairs distinctly thickened. The posterior femur and 

 tibia moderately elongate; the tibia is stout, it and 

 the femur are slightly narrowed towards the base; the 

 femur is appressed setate on all sides with stout bristles 

 which consist of 1 at apex dorsomedially and 1 doi-so- 

 laterally, 2 others at the siibapex dorsomedially, 1 be- 

 low it medially, and another ventromedially. In the 

 dorsolateral row are 7 bristles, in the ventrolateral row 

 5 and in the ventral row 7 or 8 bristles; this tibia has 



curved, oblique bristles, 4 dorsal, 4 lateral and 4 ven- 

 tral; apex with 10 bristles. Basitai-sus nearlj- as long 

 as the next three segments. The middle femur has a 

 stout poste.roapical, 2 anterior, and 3 anteroventral 

 bristles. The middle tibia has 4 doi-sal, 3 anterior, 3 

 anteroventral, 3 posterior, 3 posteroventral, and 3 

 ventral bristles. ^\jiterior femur with a ventral 

 fringe of about 10 long, slender bristles ; anterior tibia 

 with 6 or 7 dorsal bristles, part of them quite short, 

 and 4 exceptionally long posterior bristles. Tarsi end 

 in large, ribbed pulvilli ; empodium two-thirds as long 

 as claws, and end in sharply pointed claws bent chiefly 

 at the apex. 



Wings: The wings are hyaline; the marginal cell is 

 closed with a short stalk; the anterior branch of the 

 third vein ends at or barely above the wing apex ; first 

 posterior cell slightly narrowed at the middle from 

 above and below; fourth posterior cell closed with a 

 long stalk, rather convex anteriorly; anal cell closed; 

 second basal cell ends with two vems; the second sub- 

 marginal cell takes origin shortly beyond the end of the 

 discal cell : alula large, ambient vein complete. 



Abdomen: The abdomen is relatively stout and as 

 wide as the mesonotum; the first two tergites are more 

 or less flattened across the middles, but otherwise the 

 abdomen is subcylindrical to the end of the fifth seg- 

 ment ; in the females the abdomen becomes laterally 

 compressed at this segment. The first tergite is strongly 

 swollen laterally and convex and anteriorly ridged. 

 Pile of the abdomen fine, flat appressed and setate ; the 

 sternal pile is mostly long and scanty on the basal 

 sternites, sliort and appressed posteriorly. Sides of the 

 first and second tergites with considerable long, fine 

 pile. Stout bristles present on the tergites. The firet 

 tergite has 2 or 3 exceptionally long bristles; the pos- 

 terior submargins of the remaining tergites bear 2 or 

 more, stout bristles laterally ; second and tliird tergites 

 with 2, third and fourth tergites with 3 or 4 each, sixth 

 tergite with 4 or 5 bristles. On these tergites the bristles 

 gi-ow weaker toward the middles of the tergites and 

 toward the lateral margins. All sternites laterally have 

 distinct bristles though rather long and weak. Males 

 with eight tergites. the eighth more than half as long 

 as the seventh but both reduced : seven tergites present 

 in the female, the eighth forms part of the ovipositor, 

 ^lale ternimalia prominent but quite short and robust. 

 The superior forceps are convex and obtuse with an 

 apical notch instead of a dorsal notch and curved to the 

 midline ; proctiger protruded and erect ; including the 

 eighth segment, the whole dorsal part tilts upward; 

 gonopod short and obtuse. Hypandriuni large, rela- 

 tively long and transvei-se; aedeagus of three united 

 prongs; cavity open below. Female terminalia rela- 

 tively short ; the eighth tergite is strongly compressed 

 but the corresponding sternite is cylindrical instead; 

 this segment is a little longer than the seventh. Ninth 

 and tenth segments very much smaller, of about equal 

 length and moderately compressed. No spines present. 



Distribution : Xearctic : Stilpnogaster auriannulatus 

 Hine (1906). 



