PLECOPTERA OF NORTH AMERICA 111 



Alloperla pacifica Banks. 



(Plate 22, figs. 2, 3.) 



1895. Chloroperla pacifica Banks, Trans. Am. Ent. Soc, 22:313. 

 1907. Alloperla pacifica Banks, Can. Ent., 39:329. 

 1907. Alloperla pacifica Banks, Cat. Neurop., p. 13. 



Length to tip of wings, male, 9.5-10 mm.; expanse, 

 male, 16-18 mm., length to tip of wings, female, 11-12 

 mm. ; expanse, female, 19-21 mm. 



General color yellowish with the lateral margins of 

 pronotum blackish. Head slightly wider than prothorax, 

 yellowish, a little darker on clypeus; lateral tubercles 

 and frontal ridge weakly indicated ; a narrow black ring 

 around the ocelli; hind ocelli a little closer to eyes than 

 to each other ; antennae yellow, darker toward the tip. 



Prothorax transversely oval, wider than long; yellow 

 to yellowish brown ; pronotum with black or dark brown 

 lateral margins; disc slightly rugose, the rugosities 

 sometimes a little darker. Legs yellowish, tarsi a little 

 darker. Wings pale yellowish hyaline, veins yellow to 

 brownish. 



Abdomen yellow with a broad blackish median dorsal 

 stripe. Cerci yellow. 



Male. Anterior margin of eighth abdominal tergite 

 with a raised, transverse tubercle notched at posterior 

 margin ; (in pinned specimens this appears to be on the 

 seventh tergite) tenth tergite deeply and widely cleft; 

 ninth tergite with a median depression in which the su- 

 pra-anal process normally lies; supra-anal process re- 

 curved, flattened and broadly spatulate ; subanal lobes 

 small, unmodified; ninth sternite somewhat produced and 

 truncate behind. 



Female. Eighth abdominal sternite with a broadly 

 rounded sub-genital plate which in dried specimens ex- 

 tends over the entire ninth sternite or even on to the 

 tenth ; the plate normally bulges out considerably in the 

 center. 



Distribution. — Type, female No. 11347, May, Skoko- 

 mish River, Wash. (Banks Coll., Mus. Comp. Zool., Cam- 

 bridge, Mass.) ; three females, May 2, 14, 18, Bon Accord, 

 B. C; two females, July 9, 1901, Port Renfrew, B. C, in 

 Banks Collection ; five females, six males, 1878, Reno, 

 Nev. (Morrison) ; one female, two males, May 17-29, 

 Yosemite Valley, Calif. (E. C. Van Dyke) ; one female, 

 June 14, 1908, Lagunitas, Marin Co., Calif. (E. C. Van 

 Dyke) ; one female, July 25, 1907, Mt. Jefferson, Oregon 

 (J. C. Bridwell) ; one female, May 31, Cultis Lake, Chilli- 

 wock, B. C. (F. C. Ewing). 



