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U. S. NATIONAL MUSEUM BULLETIN 216 



PART 3 



ferruginous, in the male the second tergite sometimes and third ter- 

 gite rarely with a median subapical transverse fuscous area; fourth 

 tergite of male usually ferruginous basally, sometimes mostly ferrugi- 

 nous ; fourth tergite of female usually entirely black but sometimes fer- 

 ruginous basally; seventh tergite of female with a rather narrow 

 median white stripe. 



Specimens (32 cf, 589): From Maine (Bar Harbor, Belfast, Casco, 

 Lincoln Co., and Winthrop); Michigan (Bay Co., Douglas Lake, 

 Gladwin Co., Huron Co., Iosco Co., Isabella Co., Midland Co., Mus- 

 kegon, Newaygo Co., Otsego Co., Saginaw Co., and Wexford Co.); 

 New York (Adirondack Mts., Ithaca, Lake Placid, McLean Bogs 

 Reserve, Michigan Hollow Swamp in Tompkins Co., and Oswego); 

 Nova Scotia (Baddeck and Petite Riviere [Bridge]) ; Ohio (Put-in- 

 Bay) ; Ontario (Dow's Swamp near Ottawa, Grand Bend, London, and 

 Parr Island in East Spence Lake); Quebec (Abbotsford, Ivnowlton, 

 Lac Brule, and Norway Bay); Saskatchewan (Dundurn, Prince Al- 

 bert National Forest, Redberry, and Waskesiu [Lake]) ; and Vermont 

 (Ascutney, Newport, and Woodstock). 



Dates of collection are from late spring to early faU, with most of 

 them in July and August. The earliest and latest dates are: May 16 

 at Dundurn, Sask.; May 30 in Saginaw Co., Mich.; August 23 in 

 Michigan Swamp, Tompkins Co., N.Y.; August 29 in Lincohi Co., 

 Maine; and September 18 to 20 at Belfast, Maine. 



Reared specimens are as follows: 9, from Salix gall, London, Ont., 

 Apr. 2, 1953, W. W. Judd. 9, reared probably from Euura gall on 

 white willow, at St. Paul, Minn., Jan. 27, 1908. 



This species ranges from Maine to Alberta, in the Transition and 

 Canadian zones. It appears to be parasitic on sawfly gaUs on Salix. 



Figures 25, 26. — Localities: 25 (left), Gambrus apicatus; 26 (right), G. tunicularubra. 



