PLECOPTERA OF NORTH AMERICA 167 



3. Small species, 9-13 mm. long; radial sector with 



two branches ; male with a globose, membra- 

 nous supra-anal lobe; female with a narrowly 



notched subgenital plate brevis 



Larger species, 18 mm. long; radial sector with 



three branches ; supra-anal process of male 



composed of a median, chitinized knob, with a 



membranous wing each side; female unknown 



thyra 



4. Supra-anal process of male with a median, slen- 



der, chitinized rod, partly surrounded by a 

 membrane; female subgenital plate broad and 

 evenly rounded and reaching almost entirely 



across the ninth sternite arcuata 



Supra-anal process of male without a median chi- 

 tinized rod, globose and membranous ; female 

 plate either not produced or somewhat pro- 

 duced and evenly rounded or emarginate in the 

 middle 5 



5. Subgenital plate of female not at all produced; 



males 16 mm. long, females 20 mm. long__a////a 

 Subgenital plate of female somewhat produced ; 

 males less than 16 mm. long; females 15-18 

 mm. long 6 



6. Subgenital plate of female emarginate, color 



brown; male unknown maria 



Subgenital plate of female evenly rounded, color 

 usually dirty yellowish; male genitalia as in 

 anna cornelia 



Peltoperla cornelia Needham and Smith. 



(Plate 31, figs. 4, 5, 6.) 

 1916. Peltoperla cornelia Needham and Smith, Can. Ent., 48:84. 

 1916. Peltoperla dorothea Needham and Smith, Can. Ent., 48:84. 

 1916. Peltoperla ada Needham and Smith, Can. Ent., 48:86. 



Length to tip of wings, male, 12-14 mm. ; female, 14-18 

 mm. Expanse, male, 22-28 mm. ; female, 24-30 mm. 



General color yellowish to brown. 



Head yellow, usually with a diffused spot over the me- 

 dian area in front of the ocelli ; and usually black on the 

 inside of the ocelli; ocelli closer to the eyes than to each 

 other; antennae yellowish, somewhat darker towards the 

 tip. 



Prothorax wider than head, yellowish to brownish; 

 nearly twice as wide as long; front margin slightly con- 

 cave; hind margin broadly rounded; somewhat narrowed 



