PLECOPTERA 0¥ NORTH AMERICA 77 



21. With two black stripes upon a yellow prothorax. 



Cleft of the 10th tergite in the male shallow 



liictuosa 



Prothorax not so marked; 10th tergite of male 

 deeply cleft 22 



22. In the hind wing the 2nd anal vein is pectinately 



6 to 7-branched. Ocelli very large ramosa 



In the hind wing the 2nd anal vein is 3 to 5- 

 branched 23 



23. Head and prothorax yellowish above; male geni- 



tal hooks of the 10th tergite small and incon- 

 spicuous opposed by low lobes on the 8th and 



9th tergites kansensis 



Head and prothorax obscure brownish ; the geni- 

 tal hooks of the 10th tergite in the male are 

 very large and reach far forward 24 



24. With a rounded ventral hammer on the enlarged 



9th sternite and no dorsal processes opposed to 



the hooks 25 



With no hammer on the 9th sternite, but with 

 dorsal lobes on 5th tergite, opposed to genital 

 hooks 26 



25. Subgenital plate of female straight-edged 



languida 



Subgenital plate of female with a shallow median 

 recession sabulosa 



26. Genital hooks of male sharply pointed. Dorsal 



lobe of abdominal segment 5 with a narrow 

 median apical notch. Female subgenital plate 



notched in the middle of a broad border 



immarginctta 



Genital hooks of male bluntly pointed ; dorsal lobe 

 of segment 5 with a wide rounded apical cleft. 

 Female subgenital plate produced to rearward 

 in a pair of teeth that stand beside and inclose a 

 narrow notch media 



Perla innubila, new species 



(Plate 12, fig. 6; plate 17, fig. 20.) 



Length to wing tips, female, 22 mm. ; expanse, 38 mm. 



Color brown varied with yellow. Head brown above 

 with a yellow cross band upon the middle half of the oc- 

 ciput, a pair of pale yellow triangles pointing inward be- 

 tween the lateral ocelli and the eyes, and all the front of 

 the head before the antennae yellow. Antennae and palpi 



