THE C'AXADIAX ENTOMOLOGIST. 225 



A NEW CANADIAN GEOMETRID. 



BY JOHN A. GROSSBECK, AM. MUS. N.\T. HISTORY, NEW YORK. 



The Geometrid liere described was originally sent me among other 

 species for determination by Dr. C. Gordon Hewitt, entomologist to the 

 Dominion Experimental Farms, Ottawa. It was determined as probably 

 new, and was later returned to me by Mr. Arthur Gibson in a good series, 

 with the request that I describe it. I am unable to find any description 

 that will cover the species, so I am calh'ng it : 



Selidosema Manitoba^ new species. 



Expanse, 27-34 mm. Head, thorax and abdomen with mixed 

 grayish-brown and white scales, the latter sometimes almost absent, and 

 sometimes, on the abdomen, predominating. A blackish spot at the base 

 of each antenna, a bar of (he same colour across the middle of the frons, 

 and the posterior edge of the patagia and first three abdominal segments 

 black. Ground colour of wings slaty-brown, verging toward paler gray, 

 and occasionally in the median area of the primaries becoming wholly 

 white. Basal line of primaries absent. Intradiscal line geminate, black, 

 rather evenly curved outwardly, but slightly drawn in on the veins ; 

 extends from one-fourth out on costa to one-fifth or less on inner margin. 

 A median line, rather narrow and diffuse and usually incomplete, passes 

 across the centre of the wing. In the specimens with white median areas 

 this line is absent, or shows merely as a point in several places. Extra- 

 discal line black, moderate in width, evenly scalloped between the veins, 

 and in general curving outward from the costa to vein Cug, then inward 

 to inner margin. A broken denticulate white line is sometimes present in 

 the outer area. A whitish, subapical patch (intensified in the specimens 

 with white centres) is also usually present in the outer area, the inner 

 border of which touches the extradiscal line. Terminal line represented 

 by a series of black triangular marks between the veins pointed inwardly. 

 Discal spot, when present, a moderate sized ring pupilled with white. 

 Fringe concolorous with the ground, tending to become checkered 

 in some specimens. Secondaries with intradiscal line straight, 

 broad and diffuse, occasionally showing on inner half of wing. Extra- 

 discal line more defined, roundly denticulate, and in its course resembling 

 that of the fore wing. Fringe and discal spot as in fore wing, but the 

 latter never distinctly pupilled. Beneath, whitish or grayish, heavily but 

 finely speckled with brown. The extradiscal line is sometimes strongly 



July, 1911 



