PLECOPTERA OF NORTH AMERICA 81 



Male holotype, female allotype, Cornell University Col- 

 lection, from Missouri (C. R. Crosby). 



Perla expansa Banks. 



(Plate 11, fig. 7; plate 17, figs. 4, 5, 6.) 

 1920. Perla expansa Banks, Bull. Mus. Comp. Zoo!., 64:317. 



Length to tip of wings, male 18-19 mm.; female, 21 

 mm. Expanse, male, 30-34 mm. ; female, 36 mm. 



General color brown, with a median light yellow line 

 extending over the prothorax and top of head ; last two 

 segments of abdomen yellow. 



Head as broad as prothorax, ocellar triangle nearly 

 twice as broad as long, the posterior ocelli closer to the 

 eyes than to each other. The lateral anterior margin 

 raised and darker toward the eyes ; the inner area near 

 the raised margin with a number of dark wavy lines ; 

 clypeus infuscated with a darker spot near the postero- 

 lateral angle. A black V-shaped mark connnects the ocelli 

 and extends forward and outward about half way to the 

 margin so that the black mark takes the form of a short 

 and broad H. A dark rounded mark half way between the 

 compound eye and the black ocellar mark. Area in front 

 of and behind ocellar triangle light yellow; rest of head 

 dark brown ; back of head rugose. Antennae and palpi 

 brown, antennae darker toward the tip. 



Prothorax yellowish brown, a little wider than long, 

 somewhat widened behind, anterior and posterior mar- 

 gins slightly convex, angles broadly rounded; a median 

 yellow band slightly narrowed in the middle ; a transverse 

 sulcated line near the anterior and posterior margins ; 

 rugosities rather coarse and restricted largely to the in- 

 ner halves of the sides of the disc ; meso- and metathorax 

 shiny dark brown, each with a light spot near the middle, 

 mesothorax with a narrow median longitudinal line. Front 

 wings brownish infuscated in the region of the cord; 

 veins dark brown except the base of costa and subcosta, 

 hind wings hyaline except for the brownish outer one- 

 third. 



Legs light brown, tibia with a narrow dark transverse 

 band near the proximal end, tarsi darker. 



Abdomen dark brown, with segments 9, 10 and 11 light 

 yellow ; tails yellow, hairy, the basal segments very short. 



Male. Abdominal segments normal to the 9th, which 

 is shortened above and greatly lengthened beneath api- 

 cally, its subgenital scoop-like prolongation being broadly 

 oval and thinly clad with hairs over the upturned surface. 



