PLECOPTERA OF XORTH AMERICA 231 



Holotype, male, March, 15, 1898, Seattle, Wash. (Cornell 

 University). 



Allotype, female, April 28, 1898, Seattle, Wash. 



One female, April, 14, 1899, Seattle, Wash.; three fe- 

 males, June 6, 1920, Shasta Springs, Calif. (C. L. Fox) ; 

 one female, June 10, 1921, Yosemite Valley, Calif. (E. C. 

 VanDyke). 



Leuctra occidentalis Banks. 



(Plate 41, figs. 6-8; plate 42, fig. 12.) 

 1907. Leuctra occidentalis Banks, Can. Ent., 39:329-330. 



Length to tip of wings, male, 6.5-8 mm. ; female, 7-8.5 

 mm. Expanse, male, 11-13.5 mm. ; female, 12-15 mm. 



General color dark brown or black. Head wider than 

 prothorax, blackish ; occiput somewhat rugose ; covered 

 with fine pile; hind ocelli about three times as close to 

 eyes as to each other. Prothorax not narrowed behind, 

 hardly wider than long ; angles rounded ; median field not 

 over a sixth the width of pronotum ; disc of pronotum 

 quite rugose. Legs brown. Wings rusty fumose; one or 

 two Cu crossveins beyond M-Cu crossveins. 



Male. Tergites of abdominal segments unmodified ex- 

 cept ten which is partly cleft and posteriorly produced 

 on each side into two short triangular processes; supra- 

 anal lobe normally recurved under the tenth tergite, but 

 when drawn out it is produced into a triangular process 

 with a long median upcurved prolongation ; cerci modified 

 into chitinous processes with a large terminal and a ven- 

 tral tooth and about half way between these teeth often 

 another small tooth; subanal lobes modified into a long 

 probe with the bases drawn back underneath the subgen- 

 ital plate where they unite into a long upcurved probe; 

 ninth sternite produced into a short, truncate subgenital 

 plate ; ventral lobe short, rounded, as wide as long. 



Female. Eighth abdominal sternite produced into a 

 broadly emarginate subgenital platy3, beset with long 

 hairs, and covering most of the ninth sternite which is 

 heavily chitinized. 



Distribution. — Type, female, 11370, Laggan, Alberta, 

 July 23, 1901 (Banks Collection, Museum of Comparative 

 Zoology, Cambridge, Mass.) ; four males, four females, 

 Boulder, Colo. (G. S. Dodds) ; two females, Reno, Nev., 

 1878 (Morrison) ; one male, Olympia, Wash., June 2, 1895; 

 one male, Palo Alto, Calif., March 26, 1895; one male, 

 Lake Tahoe, Calif. (H. C. Hubbard) ; one female, Olympia, 

 Wash., May 27, 1895; two females, Olympia, Wash., June 



