PLECOPTEKA OF NORTH AMERICA 67 



with dark brown. Wings with fine yellowish-brown vena- 

 tion, an irregular network of crossveins occupying the 

 tip of the wing in the region between radius and the an- 

 terior branches of the sector; a little less than the first 

 half of the costal area beyond the humeral crossvein free 

 from crossveins. 



Both long and short winged males ; in the latter the 

 wings are not greatly shortened, they extend to the tip of 

 the abdomen. Five pairs of long, white, slender, fleshy 

 finger-like, tracheal gills arranged as follows: one pair 

 widely separated on the base of the submentum, a second 

 pair on a line with the first in the articulation between 

 head and thorax, the third pair a little lateral and an- 

 terior to the base of the fore legs, the fourth pair on the 

 anterior border of the mesothorax on a line with the base 

 of the legs, and the last pair in the same relative position 

 on the metathorax. 



Male. Abdomen dark brown above and on the sides, 

 pale on the venter! Setae about three-fourths the length 

 of the body ; pale brown, conspicuously ringed with darker 

 and provided with whorls of fine bristle-like hairs toward 

 the tip of the segments. The seventh dorsal segment tri- 

 angularly produced over the eighth, and ending in a 

 strong, upright, median fork ; the eighth segment nor- 

 mal ; the ninth entire, narrow above, elongated below into 

 a conspicuous subgenital plate marked with fine trans- 

 verse striae, a median villous area set off from the lateral 

 parts by prominent carinae. The tenth segment con- 

 cealed by the ninth on the venter ; widely cleft above, each 

 lobe with an erect appendage-like process on the inner 

 posterior margin; subanal plates boat-shaped, flaring; 

 stylets entirely concealed by the para-genitals which ap- 

 pear between the posterior border of the tenth tergite and 

 the subanals, as a pair of lateral chitinous sheaths with 

 a white, membranous median portion (fig. 51). 



Distribution. — Nevada County, Calif.; San Diego, Calif. 

 April 23, 1879 (C. V. Riley). 



This species is very distinct from other known mem- 

 bers of the genus by reason of the pair of backwardly di- 

 rected processes upon the seventh abdominal segment 

 that stand opposed to the genital hooks. It differs vena- 

 tionally also in that the subcostal vein at its tip inclines 

 toward the costa rather than toward the radius. 



