178 



Jewett: Plecoptera 



Fig. 6:45. a, Hastaperla chilnualna, lateral view of male 

 terminalia; b, Paraperla frontalis, ventral view of female ter- 

 minalia (a, Ricker, 1952; b, Needham and Claassen, 1925). 



anterior corners produced into acute angles (fig. 6:46a) 

 British Columbia to Oregon delicata Frison 1935 



5. In lateral view, depth of the tip of the supra-anal 

 process about equal to half the length; central Cali- 

 fornia (fig. 6:53/) chandleri Jewett 1954 



— In lateral view, depth of the tip of the supra-anal 

 process less than 1/3 the length; British Columbia to 

 Oregon. . .(synonyms: elevata Frison 1935; thalia Ricker 

 1952) (fig. 6:48c) severa (Hagen) 1861 



6. Body of the supra-anal apparatus obscure, short, and 

 lying along the surface of and fused with the 10th 

 tergite, usually in a slight depression but never in a 

 deep groove; supra-anal process short, sharply recurved 



(subgenus Triznaka Ricker 1952) 7 



— Body of the supra-anal apparatus lying in a deep groove 

 of the 10th tergite and attached to its sides, bearing 

 at its posterior end a terminal part which is well marked 

 off from the rest of the apparatus 



(subgenus Sweltsa Ricker 1943) 8 



7. Head unmarked except for the ocellar rings; pronotum 

 yellow except for dusky lateral margins; no lobe on the 

 male 7th sternite (fig. 6:466); British Columbia to 

 California diversa Frison 1935 



— Head and pronotum with conspicuous median markings 

 of black on yellow; anterior dark mark on head about 

 twice as wide as long; a small posterior lobe on the 

 male 7th sternite; Washington to California; Colorado 

 to North Dakota and South Dakota 



pintado, Ricker 1952 



8. A definite elevated transverse and usually notched 



Fig. 6:47. Male terminalia of Alloperla, in dorsal view, o, 

 fownesi; b, forcipata; c, tamalpa (a,c, Ricker, 1952; b, Neave, 

 1929). 



process near the anterior border of the 9th tergite ... 9 



— No process on the 9th tergite (figs. 6:46c; ?, 6:5 le); no 

 dark U-marks on meso- and metanota; margins of the 

 pronotum only faintly darkened; British Columbia to 

 California fraterna Frison 1935 



9. A bifurcate transverse process on the 8th tergite (figs. 



6:49a; ?, 6:51/); Montana to California 



(synonym: A. spatulata 



Needham and Claassen 1925) pacifica (Banks) 1895 



— No process on the 8th tergite 10 



10. Disc of the pronotum clear yellow; supra-anal process 



terete, slender, bluntly pointed (figs. 6:46d; ?, 6:51c); 

 British Columbia to Oregon exquisita Frison 1935 



— Disc of the pronotum with black reticulate markings 

 11 



11 



12 



Supra-anal process slender, somewhat expanded in 



dorsal view toward the tip 12 



Supra-anal process broadly flattened 15 



Supra-anal process extending barely beyond the 10th 

 tergite (fig. 6:47c; ?, 6:506); Mt. Tamalpais, California 

 tamalpa Ricker 1952 



wmm 



Fig. 6:46. Male terminalia of Alloperla, in dorsal view with 

 enlarged dorsal view of tip of supra-anal process for a, c and d. 

 a, delicata; b, diversa; c, fraterna; d, exquisita (Frison, 1935). 



Fig. 6:48. Mole terminalia of Alloperla, in dorsal view, a, 

 continua; b, fidelis; c, severa; d, pallidula {a,b, Needham and 

 Claassen, 1925; c,d, Frison, 1935). 



