173 



Jewett: Plecoptera 



adult male with a slender, erect supra-anal process; 

 Appalachian 



...(subgenus Allonarcys Needham and Claassen 1925)'° 

 Nymphs without paired lateral projections on the 

 abdomen; adult male with a massive decurved supra- 

 anal process Pteronarcys, s.s. Newman (1838) 4 



. Nymph with lateral thoracic processes long, slender, 

 directed outward and wing pads pointed; erect lobes 

 of the divided 10th tergite of male rather broadly 

 rounded (fig. 6:35a); processes on the apex of the 

 female subgenital plate are somewhat equilateral 

 triangles approximated at the base (fig. 6:35a"); British 



Columbia to California calif ornica Newport 1851 



Nymph with lateral thoracic processes short, not 

 markedly directed outward and wing pads rounded; erect 

 lobes of the divided 10th tergite of the male rather 

 narrow, much higher than wide (fig. 6:35&); processes 

 at the apex of the female subgenital plate are very 

 elongate triangles, twice as high as broad and more 

 widely separated at the base (fig. 6:35c); British 



Columbia to California 



princeps Banks 1907 



Suborder SETIPALPIA 



Family PERLODIDAE 



This family, confined to the Holarctic region and 

 North America, is very rich in species, about eighty 

 of which have been described to date. These have 

 been placed in three subfamilies by Ricker in his 

 recent monograph of the world fauna of this family 

 (Ricker, 1952, pp. 62-145). Ricker's classification of 

 this family is adopted here. The male genitalia must 

 be relied upon for placing many species to subfamily. 

 Keys to Ricker's subgenera and to California species 

 of the family are included below. 



Subfamily ISOGENINAE 



Members of this subfamily are placed in two genera, 

 Arcynopteryx Klapalek 1904 and Isogenus Newman 

 1833. The former includes seven subgenera in North 

 America, four of which definitely occur in California. 

 One of these, Oroperla, occurs in streams of the 

 Sierra Nevada, but adults have not yet been taken; 

 their discovery will be of great interest. Isogenus is 

 divided into twelve North American subgenera, four of 

 which are known to occur in California. An additional 

 species found in the state, /. sorptus (Needham and 

 Claassen) 1925 (fig. 6:36c) has not been placed in a 

 subgenus as only the female is described. The sub- 

 genus Isogenoides has not been recorded in California 

 but the species Isogenoides frontalis colubrinus 

 Hagen 1874 (figs. 6:7z; 6:36a, d) very probably occurs 

 in some of the larger coastal streams of the northern 

 part of the state. 



P. (Allonarcys) proteus Newman is recorded by Needham 

 and Claassen (1925) from California; this is regarded as a 

 probable error. 



Fig. 6:36. o, Isogenus frontalis colubrinus, ventrol view of 

 female terminalia; b, I sogenus alameda, dorsal view of male 

 terminalia; c, Isogenus sorpfus, head and pronotum of female; 

 d, I sogenus f. colubrinus, lateral view of male terminalia (a,d, 

 Hanson; 1943; b, Needham and Claassen, 1925; c, Ricker, 1952). 



Key to the North American Subgenera and California 

 Species of Arcynopteryx 



1. Lateral abdominal gills present (adult unknown); 

 California (sub- 

 genus Oroperla Needham 1933) barbara (Needham) 1933 



— Abdominal gills absent 2 



2. Three pairs of thoracic gills and 1 pair of cervical gills 

 present (fig. 6:37a 7 , 17); Washington to California 



(synonym: .4. vagans Smith 1917) (subgenus Per- 



linodes Needham and Claassen 1925) aurea Smith 1917 



— Cervical gills absent 3 



3. Gills present on meso- and metathorax, absent from 

 prothorax; Cordilleran but not known in California. 



(subgenus Setvena Ricker 1952) 



— Gills present on all 3 thoracic segments, or entirely 

 absent from the thorax 4 



4. Gills present on all 3 thoracic segments (fig. 6:376); 

 Washington to California in Alpine Zone 



(subgenus Megarcys 



Klapalek 1912) yosemite (Needham and Claassen) 1925 



— Gills absent from the thorax 5 



5. Transverse mesosternal ridge present in adult; nymphal 

 lacinia tapered to a short terminal spine which is equal 

 to 1/4 of the total lacinial length (fig. 6:37a, c); British 

 Columbia to Oregon 



(synonym: .4. walkeri Ricker 1943) 



(subgenus Frisonia Ricker 1943) picticeps Hanson 1942 



— Transverse mesosternal ridge absent; terminal spine 

 of nymphal lacinia equal to 1/3 or more of the total 

 length 6 



6. Male supra-anal process very long and needlelike; 



"Adapted from Ricker (1952). 



