164 



Jewett: Plecoptera 



Fig. 6:19. Nemoura product a, basal abdominal segments of 

 male in lateral view (Frison, 1937). 



— A pair of gills on each side of the pro- and mesothorax, 

 a single gill on the sides of the metathorax (fig. 



6:18<x,d); California and Nevada (subgenus Sierra- 



perla Jewett 1954) cora Needham and Smith 1916 



3. Length to tip of wings of male, 9-11 mm., of female, 

 10-13 mm. (fig. 6:186, c,/); Pacific Coast and Alta .. 



brevis Banks 1907 



Length to tip of wings of male, 11 mm., of female, 14-15 

 mm.; British Columbia to Oregon 



mariana Ricker 1943 



4. Two pairs of gills on the side of the mesothorax and 

 metathorax set just above the coxae; one pair near 

 the posterior edge of the metasternum projecting from 

 under the produced sternal plate; one pair projecting 

 from under the subanal lobes; eastern North America 



(subgenus Peltoperla Needham 1905) 



— One pair of gills each on the meso- and metathorax; no 

 other external gills 5 



5. Male supra-anal process with a slender tip; known only 

 from Tennessee .. .(subgenus Viehoperla Ricker 1952) 



zipha Frison 1942 



— Male supra-anal process strongly sclerotized and 

 complex in shape; Pacific Coast .. .(subgenus Soliperla 

 Ricker 1952) 6 



6. Aedeagus of male with a large bilobed sclerotized 

 process (fig. 6:18e) thyra Needham and Smith 1916 



— Aedeagus with 4 sclerotized spines (fig. 6:53a) 



quadrisp inula Jewett 1954 



Family NEMOURIDAE 



Subfamily NEMOURINAE 



This is a large subfamily with representatives on 

 all continents. All the North American species are 

 placed in Nemoura, twenty-four species of which 

 have been described to date. This fauna has been 

 recently monographed by Ricker (Ricker, 1952, pp. 

 10-61) who places the species in twelve subgenera. 

 The adults of described California species can be 

 placed with the following key. The nymphs of so 

 many species remain unknown that it is impractical 

 to present a key to the known species; however, 

 specimens with gills can be placed in the proper 

 subgenera by using the adult keys. 



Fig. 6:20. Male terminalia of Nemoura, in lateral view, a, co/umbiano; b, nevac/ensis interrupta; 

 c, frigida; d, nevadensis nevadensis; e, oregonensi's, f, cinctipes (Needham and Claassen, 1925). 



