178 U. S. NATIONAL MUSEUM BULLETIN 216 



Oregon (Bare Island in Klamath Lake and Warrenton); Prince 

 Edward Island (Dalvay House in Canadian National Park) ; Quebec 

 (Aylmer, Burbridge, Cascapedia, Montreal, Norway Bay, and "St. 

 John"); Saskatchewan (Atten Lake, Bateman, Christopher Lake, 

 Prince Albert National Park, Saskatoon, Swift Current, and 

 Waskesiu) ; South Dakota (Vernon) ; Vermont (Grand Isle) ; Washing- 

 ton (Big Four, Dungeness, Forks, Mount Rainier at 2,900, 5,300 

 and 5,700 ft., O'Sullivan Dam in Grant Co., Snoqualmie Pass, 

 Thorpes in Klickitat Valley, and White River on Mount Rainier); 

 Wisconsin (Columbus and Madison); and Yukon Territory (Snag). 

 We have specimens also from Cherkes Forest on Cyprus and from 

 Vladivostock in Siberia. 



Most dates of capture are from about May 20 to late August. The 

 only records prior to May 20 and after August 31 are: April 18 in 

 Douglas Co., Kans.; May 2 in Midland Co., Mich.; May 7 in Washing- 

 ton Co., Minn., at Alto, Mich., and at Cleveland, Ohio; May 10 at 

 Mount Pleasant, Iowa; May 12 at Ames, Iowa, and at Davis, Calif.; 

 May 11 in Putah Canyon, Solano Co., Calif.; May 16 in Bedford Co., 

 Ohio; September 1 at Timagami, Ont.; September 4 at Crookston, 

 Minn.; September 8 at Garrison, Minn.; September 15 and October 18 

 at Davis, Calif.; September 18 in Midland Co., Mich.; and October 

 22 in Mille Lacs Co., Minn. 



This species is Holarctic. In America, it is transcontinental in 

 the Canadian and Transition zones. Adults occur mostly from 

 midspring to early fall. 



II. OCULATORIA GROUP 



Areolet present except in T. zonata, when present pointed above 

 or narrowly sessile; carina between metapleurum and metasternum 

 complete; propodeum without a distinct dorsolateral longitudinal 

 ridge. 



Face of male white, of female white to black, usually black with 

 white orbital marks; frons with narrow to wide white orbital mark. 



Two species of this group occur in our region. All of the Palaearctic 

 species that we have seen except T. variabilis belong here, and we 

 have seen species of the group also from South America, including 

 Tromatobia lineiger Morley 1914, described from Montevideo. 



2. Tromatobia ovivora (Boheman) 



Figures 331, c; 365 



Front wing of male 3.5 to 6.5 mm. long, of female 4.2 to 8.0 mm. 

 long; areolet present; upper and lateral faces of propodeum with 

 punctures that are separated by about 1.0 to 1.5 their diameter; 

 ovipositor sheath 0.36 to 0.6 as long as front wing. 



