Fig. 6:17. Nymph of Claassenia sobu/oso (Claassen, 1931). 



Mountains Atoperla Banks 1905 



Three ocelli, the anterior ocellus inconspicuous in 

 immature nymphs; body patterned; east of Rocky Moun- 

 tains Perlinella Banks 1900 



A closely set row of spinules across the back of the 



head, usually set on a low ridge (fig. 6:16) 27 



Occipital ridge absent; spinules absent from back of 



head except at the sides 28 



Three ocelli 29 



Two ocelli set close together; east of Rocky Mountains 



Neoperla Needham 1905 



Two ocelli; south of U. S. border; one record from Texas 



Anacronevria Klapalek 1909 



Three ocelli Acroneuria Pictet 1841 (in part) 



Abdomen without frecklelike spots 30 



Abdomen covered with freckles; east of Rocky Moun- 

 tains Perlesta Banks 1906 



163 

 Jewett: Plecoptera 



30. Dorsal surface patterned .'11 



— Dorsal surface almost uniformly brown; eastern V.rtti 

 America A crone <iria rur.i 



31. Anal Kills present (fig. 6:17) 39 



— "Anal gills absent; east of Rocky Mountains 



Paragnetina Klapalek 1907 



32. Abdominal segments yellow, broadly bordered with 

 black; east of Rocky Mountains 



N e ophasqanophora Lestage 1922 



— Abdominal segments almost wholly brown; western 

 North America Claassenui Wu 1984 



Suborder FILIPALPIA 



Family P ELTOP ERL ID AE 



Members of this family are found in (lie Americas 

 and in eastern Asia and bordering islands. Their 

 roachlike body form is quite unlike that of any other 

 group of stoneflies. The North American fauna con- 

 sists of eleven described species which were placed 

 in four subgenera of Peltoperla by Rickcr (Ricker, 

 1952, pp. 152-157); one of these has been further 

 divided by Jewett (19546). Three subgenera occur in 

 California, the species of which can be separated 

 by the following key. Nymphs are not keyed because 

 those of only a few species are known. The gill 

 characters in the adult key can be used to place 

 specimens of nymphs to subgenus. 



Fig. 6:18. Terminalia of Peltoperla. a, cora, ventral view of 

 female; b, brevis, dorsal view of male; c, brevis, ventral view of 

 female; d, cora, ventral view of male; e, thyra, lateral view of 

 male; f, brevis, ventral view of male (Needham and Claassen, 

 1925). 



Key to the North American Subgenera and Adults of 

 California Species of Peltoperla 



1. One pair of cervical gills 2 



— No cervical gills 4 



2. Two pairs of gills on the side of all 3 thoracic segments 

 (subgenus Yoraperla Ricker 1952) 3 2 



2 P eltoperla nigriscens Banks 1948, from Sequoia National 

 Park may be a synonym of P. brevis; the original description 

 is inadequate to distinguish it. 



