PLECOPTERA OF NORTH AMERICA 65 



middle band of the pronotum occupies the entire middle 

 field; in the female it is less conspicuous, but the lateral 

 portions show light areas. The under side of the head is 

 yellow-brown with a black-brown throat ; otherwise the 

 under side is black-brown, the venter of the female is 

 lighter. Antennae black-brown, palpi dark brown. Legs 

 dark brown, femora narrowly bordered with yellow-brown 

 on the ventral edge, and broadly on the dorsal ; tibiae yel- 

 low-brown for the most part. Setae shining bright brown. 



Head not as long as usual in the species of this genus 

 and a little narrowed anteriorly. Eyes moderately large 

 and spherically rounded, behind them there are short 

 tempora. Ocelli small, forming an isosceles triangle ; the 

 distance between the posterior ocelli is more than half 

 longer than the distance from the inner margin of the 

 eyes and from the anterior ocellus (30:20:22). The crown 

 suture distinct, the occipital furrow deep. Tubercles large, 

 broadly oval, equally distant from the posterior ocelli and 

 the inner margin of the eyes. The cuticle is fine, but with 

 prominent reticulate wrinkles, and outside the tubercles 

 and the M-shaped mark it is studded with scattered pits 

 bearing bristles. 



Pronotum slightly trapezoidal, narrower in front than 

 the occiput, a little widened posteriorly (50:53:47). An- 

 terior and posterior borders broad, convex ; sides straight. 

 Middle furrow narrow but deep ; the middle area very 

 broad, occupying in the first third almost a fifth of the 

 entire breadth, widened anteriorly and posteriorly. The 

 structure is similar to that of the head. 



In the male the wings are greatly shortened, so that the 

 anterior ones reach the posterior border of the second 

 segment, and the posterior ones the posterior border of 

 the third segment. In both sexes they are conspicuously 

 smoked. The network in the tip of the wing occupies the 

 space between radius, its sector, and the several branches 

 of the same ; but it is comparatively simple and composed 

 of large, not very irregular cells. The inner inter-radial 

 cell of the fore wing is a little more than once and a half 

 as long as its base. 



In the male the ninth segment is prolonged into a yel- 

 low-brown, parabolic, subgenital plate, the tenth seg- 

 ment is cleft on the dorsal side with mallet-like processes. 

 The other parts show no departure from the usual form. 



The female subgenital plate is short, semicircular, 

 bright brown, and does not appear notched on the pos- 

 terior margin. 



