PLECOPTERA OF NORTH AMERICA 147 



General color blackish with greenish-hyaline wings. 

 Head wider than prothorax; dark brown to blackish, us- 

 ually with yellow between the hind ocelli and just beside 

 the eyes and sometimes also yellow on clypeus; lateral 

 tubercles and frontal ridge moderately prominent; hind 

 ocelli closer to eyes than to each other. Antennae blackish. 



Prothorax dark brown with blackish rugosities; wider 

 than long, not appreciably narrowed behind ; sides 

 straight ; angles square ; disc quite rugose. Legs blackish. 

 Wings greenish-hyaline ; subcosta does not reach to the 

 cord ; several costal crossveins before the end of subcosta 

 and one beyond. 



Abdomen blackish; tails yellowish at base, dark to- 

 wards the tip. 



Male. Ninth abdominal sternite much produced and 

 rounded behind ; eighth sternite with a yellow transverse 

 knob on the hind margin; tenth tergite medially de- 

 pressed ; subanal lobes recurved, short, pointed ; penis, 

 when extended, membranous with a forked chitinous proc- 

 ess as shown in Plate 26, figure 4. 



Female. Subgenital plate of eighth abdominal ster- 

 nite somewhat produced, broadly rounded and medially 

 emarginate, sometimes with a wide shallow notch. 



Distribution. — Holotype male, allotype female, July 12, 

 1923, Waterton Lakes, Alberta, Can. (J. McDunnough, 

 Canadian National Collection). Paratypes, two males, 

 three females from the same locality as the types. 



When pinned this species appears almost wholly black 

 with slightly greenish tinted- wings, and when placed in 

 alcohol the black color changes to a brown. 



Isoperla minuta Banks. 



(Plate 27, figs. 7, 8, 9.) 

 1900. Chloroperla minuta Banks, Trans. Am. Ent. Soc, 26:244. 

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



Length to tip of wings, male, 5.5-6 mm. ; female, 6-7 

 mm. Expanse, male, 9-10 mm. ; female, 10-11 mm. 



General color brown to blackish, wings infuscated ex- 

 cept costal margin which is yellow. 



Head hardly wider than prothorax; brown to blackish, 

 darker in the ocellar triangle ; usually a small yellow spot 

 between the hind ocelli ; frontal ridge and lateral tubercles 

 flat, shiny; hind ocelli at least twice as close to the eyes 

 as to each other. Antennae yellowish at base, dark be- 

 yond. 



Prothorax almost twice as wide as long; front and hind 

 margins rounded ; sides almost straight, angles somewhat 



