238 U. S. NATIONAL MUSEUM BULLETIN 216 



dorsally along the median line. Cheek more or less, under side of 

 scape, hind corner of pronotum, and obscure mark on subtegular 

 ridge, whitish; flagellum blackish brown, paler, below; basal half of 

 tegula whitish, the rest fulvous; front and middle legs fulvous, their 

 trochanters, coxae, and femora at apex, and basal part of their tibiae 

 and tarsi more or less tinged or marked with pale yellow; hind coxa, 

 trochanters, and femur fulvous; hind tibia white, its basal 0.15 ± 

 and apical 0.63 ± fuscous; hind tarsus whitish, the apex of the first 

 through fourth segments and apical 0.7 ± of fifth segment infuscate. 



Type: 9, Prince Albert National Park, Sask., July 19, 1941, J. G. 

 Rempel (Washington, USNM 63667). 



Paratypes: d\ Waterton, Alta., July 17, 1923, H. L. Seamans 

 (Ottawa). 9, Trinity Valley, B. C, June 20, 1937, H. Leech (Ot- 

 tawa). 9, Mount Wachusett, near Princeton, Mass., July 2, 1948, 

 W. T. M. Forbes (Ithaca), cf, Mount Marcy, N. Y., June 26, 

 J. N. Belkin (Townes). 9, Waubamick, Ont., June 5, 1915, H. S. 

 Parish (Ithaca). 9, Magog, Que., May 25, 1936, G. S. Walley 

 (Ottawa). 9, Charlestown, E. I., July 24, 1937, M. Chapman 

 (Townes). 9, Dawson, Yukon, July 17, 1949, W. W. Judd (Law- 

 rence) . 



This species is trancontinental, mostly in the Canadian zone. 



36. Exochus externus, new species 



Figures I79,k; 190,b; 194,h 



Female type: Front wing 4.3 mm. long; combined face and clypeus 

 1.04 as high as wide, in vertical plane rather strongly convex above, 

 less strongly convex below, in horizontal plane rather weakly convex, 

 their punctures moderately large and coarse, on face separated by 

 about 0.6 their diameter, sparser on clypeus; interantennal process of 

 frons somewhat incurved, its apical angle 85 degrees; median swelling 

 of frons rather strong, ventrally elongate and very protuberant, almost 

 reaching interantennal process; hind ocellus separated from eye by 

 1.00 its long diameter; median half of clypeal margin faintly concave; 

 mandible with scattered, rather small punctures, broad basally, 

 tapered to a moderately narrow apex, its lower tooth small; costula 

 represented by very short stubs; second lateral area of propodeum 

 with a few hairs basally and in its apicolateral corner; hind femur 2.10 

 as long as deep; front spur of hind tibia 2.75 as long as wide; punctures 

 of second abdominal tergite very small, rather evenly distributed, 

 their interspaces about 2.5 their diameter. 



Black. Face with a vertical yellowish triangle just laterad of each 

 antennal socket; spot at top of eye pale yellow; mouth parts stramin- 

 eous; hind corner of pronotum pale yellow shading into fulvous for- 



