PLECOPTERA OF NORTH AMERICA 155 



Isoperla montana Banks. 



(Plate 27, figs. 10, 11, 12.) 

 1898. Chloroperla montana Banks, Trans. Am. Ent. Soc, 25:199. 

 1907. Isoperla montana Banks, Cat. Neurop., p. 13. 



Length to tip of wings, male, 11.5-13 mm. ; female, 13- 

 14.5 mm. Expanse, male, 20-23 mm.; female, 23-26 mm. 

 General color yellow with brown on head and pro- 

 thorax ; wings greenish hyaline. 



Head yellow with a wide brown V-shaped mark con- 

 necting the ocelli; frontal ridge and lateral tubercles in- 

 conspicuous, hind ocelli closer to the eyes than to each 

 other. Antennae pale at base, darker beyond. 



Prothorax a little narrower than head ; wider than long, 

 slightly narrowed behind ; front and hind margins 

 rounded ; color yellow with brown rugosities on each 

 side of the disc. 



Legs yellowish, femora with a narrow transverse black 

 band at the tip ; tarsi dark. Wings greenish hyaline, veins 

 yellowish brown ; subcosta reaches almost to the cord ; 

 several costal crossveins before the end of subcosta and 

 one beyond. 



Abdomen yellowish brown ; tails yellowish at base be- 

 coming darker towards the tip. 



Male. Ninth abdominal sternite produced and evenly 

 rounded behind; eighth sternite with a transverse knob 

 on the hind margin ; subanal lobes sharp, recurved upon 

 the tenth tergite; supra-anal process not developed. 



Female. Hind margin of eighth abdominal sternite 

 produced into a broad, rounded subgenital plate which 

 normally extends almost half way across the following 

 sternite. 



Distribution. — Type, male, No. 11339, Mt. Washington, 

 N. H. (Banks Collection, Mus. Comp. Zool., Cambridge, 

 Mass.). 



New York, Ithaca, June 13, 1906; May 26, 1919; 

 May 27, 1922 (Ellis) ; Slaterville, June 13, 

 1904; Ogdensburg, July 16, 1906; Gloversville, 

 June 13, 1901 (C. P. A.) ; Coy Glen, near Itha- 

 ca, June 4, 1910; Enfield, May 21, 1922 (P. 

 M.) ; Newfield, June 5, 1923 (P. M.) ; Moore's 

 Brook, near Ithaca, May 16, 1922 (C. K. Sib- 

 ley) ; Taughannock, May 24, 1919 (H. Diet- 

 rich) ; Lakeside, Orleans Co., June 10. 

 Minnesota, St. Anthony Park, June 20. 

 Maine, Bar Harbor, June 8, 1921 (C.W.Johnson). 



