•PLECOPTERA OF NORTH AMERICA 71 



Distribution. — St. Martin's Falls, Albany River, Can- 

 ada ; Great Slave Lake ; Dawson, Y. T. Canada, July 5, 

 1912 (J. M. Jessup) ; Grand Lake, N. F., July; Grand 

 River, Canada, July 1, 1888 (L. Cabot), Apostle Is., Ash- 

 land Co., Wis., July 4-11, 1907; Niagara Falls, N. Y., June 

 24, 1901 ; Blackf oot, Idaho, June 22 (E. G. Titus). 



Isogenus elongatus Hagen. 



(Plate 10, figs. 12, 17.) 

 1875. Isogenus elongatus Hag., Bull. Geol. Surv. Terr., p. 576. 

 1907. Isogenus elongatus Banks, Cat. Neurop., p. 11. 

 1912. Isogenus elongatus Klap., Coll. Selys, 4:58. 



Length to wing tips, male (short winged) , 8 mm. ; fe- 

 male, 24-28 mm. ; to tip of abdomen, male, 14 mm. Ex- 

 panse, female, 40-44 mm. 



Color, brown varied with yellow. Head obscure brown, 

 with a faint dark polished M-mark across the front, in- 

 terrupted at the middle ocellus. An indistinct diffuse 

 crown spot of yellowish is connected posteriorly with the 

 apex of a more evident triangular spot upon the rear of 

 the head; antennae concolorous, brownish. Palpi darker 

 brown. 



Prothorax rectangular, with the usual pale mid-dorsal 

 stripe widening slightly to rear, and disappearing upon 

 the front of the mesothorax. Legs concolorous, brownish 

 except for the paler tips of the femora at the knees. 

 Wings subhyaline with brown veins, and a faint wash of 

 brown about the front end of the cord. They are so ab- 

 breviated in our male specimens as to cover only the basal 

 half of the abdomen. 



Abdomen blackish. Tails black. 



Male. Abdomen brown, becoming blackish toward the 

 tip and across the apices of segments, with a pair of ob- 

 scure submedian pale dots close to the mid-dorsal line on 

 each of the middle segments. Segment 9 is but little 

 altered from the normal, a little abbreviated dorsally and 

 elongated ventrally, but with no distinct elongation into 

 a subgenital scoop — only a little narrow median depres- 

 sion of the extreme mid-ventral apical margin with a pair 

 of impressions of the wall beside it. Segment 10 cleft 

 above, as usual. Chitinized strongly at the sides where 

 broadly exposed, thinner below. The edges of the cleft 

 above are broadly emarginate with both angles pointed, 

 the hinder one a little longer, acute, beset with about fif- 

 teen coarse prickles and erected and curved forward to 

 form a low genital hook. The U-shaped supra-anal proc- 

 ess bears a pyramidal transparent cap covered with mi- 



