PLECOPTERA OF NORTH AMERICA 135 



1852. Perla occipitalis Walker, Cat. Neurop., p. 160. 



1861. Perla occipitalis Hagen, Syn. Neurop., N. A., p. 27. 



1862. Perla occipitalis Walsh, Proc. Acad. Nat. Sci. Phil., p. 365. 

 1892. Perla occipitalis Banks, Cat. Neurop., p. 342. 



1894. Pseudoperla occipitalis Banks, Ent. News., 5:178. 



1904. Pseudoperla occipitalis Banks, Proc. Ent. Soc. Wash., 6:205. 



1907. Pseudoperla occipitalis Tucker, Kan. Univ. Sci. Bull., 4:78. 



1907. Neoperla occipitalis Banks, Cat. Neurop., p. 12. 



1908. Neoperla occipitalis Banks, Proc. Ent. Soc. Wash., 9:150. 



1909. Neoperla occipitalis Klapalek, Wien. Ent. Zeit., 28:218. 



Length to tip of wings, male 10-14 mm. ; expanse, male, 

 17-24 mm. ; length to tip of wings, female, 12-18 mm. ; ex- 

 panse, female, 21-33 mm. 



General color yellow varied with brown, with lightly to 

 heavily infuscated wings. 



Head a little wider than prothorax; yellowish with a 

 black spot over the ocelli and sometimes with an infus- 

 cated spot on the labrum. (In some specimens the black 

 spot over the ocelli is not connected between the ocelli 

 so that each ocellus is surrounded by a black ring) ; ocelli 

 two, large, less than two diameters distant from each 

 other; antennae brown to blackish, somewhat lighter at 

 the base. 



Prothorax brown, sometimes lighter in the median 

 area; considerably narrowed behind, wider than long; 

 front angles acute, hind angles rounded ; surface quite ru- 

 gose ; the grooves on the front and hind margin blackish. 

 Legs yellowish to brown, externally darker ; first and sec- 

 ond tarsal segments very short, subequal, third tarsal 

 segment much longer than one and two combined. Wings 

 lightly to heavily infuscated; veins brown except costa 

 and subcosta, which are usually yellow, especially in those 

 specimens having heavily infuscated wings; subcosta 

 ends before the cord; 8-14 costal crossveins before the 

 end of subcosta and 2-4 beyond; radial sector usually 

 three branched; several cubital crossveins in the hind 

 wing ; second anal vein of hind wing usually connected to 

 third vein by a crossvein. 



Abdomen and cerci yellowish. 



Male. Hind margin of seventh abdominal tergite with 

 a median raised, chitinous process directed backward with 

 prickles on the tip and behind; eighth tergite with a 

 median raised rounded knob beset with prickles; ninth 

 tergite with a small median and lateral raised area, all 

 beset with prickles; tenth tergite with incurved proc- 

 esses, originating at the base of the cerci, and almost 

 meeting on the mid-dorsal line of the tenth tergite. They 

 are evenly rounded and finely spin.ulose at the tip ; a little 

 distance before the tip these incurved processes bear a 



