476 U. S. NATIONAL MUSEUM BULLETIN 216 



separated by about 1.7 their diameter; second segment of middle tarsus 

 about 3.4 as long as deep; fifth segment of hind tarsus about 0.90 as 

 long as second segment; second tergite polished or subpolished, smooth 

 with a little rugosity at extreme base, its punctures sharp, separated 

 from each other by about 1.5 their diameter. 



Black. Mandible stained with ferruginous; tegula fulvous to 

 blackish brown; labrum, palpi, and front and middle legs fulvous, the 

 front and middle tarsi a little brownish apically ; hind coxa, trochanters, 

 and femur fulvous; occasionally, in small specimens from the Hud- 

 sonian zone, the hind coxa fuscous basally; hind tibia and tarsus 

 brownish fulvous; abdomen entirely black or more or less fulvo- 

 ferruginous medially, the apical 0.3 ± always black or infuscate; wings 

 subhy aline. 



Female: Front wing 5.0 to 11.4 mm. long; flagellum with about 38 

 segments, its first segment about 1.35 as long as second; head about 

 1.00 as wide across temples as across eyes; punctures on temple 

 moderately small, separated by an average of about 1.5 to 3.0 their 

 diameter; thorax about 2.35 as long as high; upper 0.25± of pronotum 

 with moderate sized, moderately strong punctures that are separated 

 by about 1.5 their diameter; groove of pronotum with about 10 short, 

 rather weak, transverse ridges that are sometimes very faint or absent, 

 especially in smaller specimens; mesoscutal punctures small, sparse, 

 separated by about 5 times their diameter; mesepimeron with hairs 

 on its upper 0.7 ± ; metapleurum with moderately large, weak, rather 

 close punctures and more or less wrinkled, especially posteriorly; 

 petiolar area about 0.45 as long as combined basal area and areola: 

 propodeal teeth about 0.9 as long as their basal width; hairs in first 

 lateral area moderately dense; hind femur about 2.00 as long as deep, 

 the punctures on its upper half rather small, sharp and dense, much 

 sparser below the middle, its lower third with very sparse punctures or 

 almost none; second segment of middle tarsus about 1.6 as long as 

 deep; fifth segment of hind tarsus about 1.35 as long as second; 

 second tergite polished, with a little rugulosity at its base, its punctures 

 very small, separated by about 3 times the length of the hairs; 

 ovipositor sheath about 1.47 as long as front wing. 



Black. Mandible often tinged with ferruginous; labrum and palpi 

 fulvous to brown; tegula f uscof erruginous ; legs fulvous or fulvo- 

 ferruginous, the tarsi often tinged with brown; abdomen black or 

 fulvoferruginous, rarely of intermediate color. 



This is an unusually variable species, and difficult to distinguish 

 from some of the closely related forms. Brevicaudus in the north, 

 curtum of lowland California, sierrae in the Sierra Nevada, and 

 parvum in the Cascades and Rocky Mountains are adjacent popula- 

 tions which are only weakly differentiated and split away from 



