90 THOMAS SAY FOUNDATION 



nent, black, shining. Eyes and rear ocelli equidistant. 

 Antennae and palpi black. 



Prothorax with narrow median groove in the yellow 

 band, and with wide transverse grooves setting off at 

 front and rear collar and cape, both of which are a -little 

 convex. Side margins straight and parallel. Embossed 

 markings in a dense double row each side next the middle 

 stripe, and a single large one farther toward the hind 

 angle ; all these bosses are shining black on the dull gray 

 background of the disc. Dorsal stripe yellow, wider behind 

 and spreading diffusely beyond the transverse grooves. 

 Thorax and legs black. Wings strongly tinted with amber 

 brown, more deeply at base and along the subcostal space. 

 The cord jogs outward on the radial sector, which 

 branches far beyond it once or twice. The costal space 

 lacks crossveins from one-half to one-third the distance 

 from humeral crossvein to the cord. The anal vein in the 

 hind wing is two-branched and not sinuate. Wing mem- 

 brane covered with a microscopic brownish pubescence. 



Abdomen black except for the yellow rear margin of 

 the 9th and 10th segments ; tails black. 



Male. Unknown. 



Female. Subgenital plate similar to that of P. varians, 

 broadly rounded, covering most of the 9th sternite, black- 

 ish in color. 



Holotype, female, North Carolina, Cornell University 

 Collection. 



Perla sorpta, new species. 



(Plate 12, fig. 4; plate 25, fig. 10.) 



Length to wing tips, female, 17 mm. ; expanse, 30 mm. 



Color brown varied with yellow. Head mostly yellow 

 above, dark brown around the sloping hind angles. There 

 is a ring of paler brown containing the 3 ocelli and en- 

 tirely surrounding a yellow crown spot between them, 

 and from this ring an obscure band of brown extends 

 obliquely forward each side to the base of the antennae. 

 Basal segment of antennae brown, the remainder lost. 

 Palpi, pale yellowish brown. Ocelli about equidistant 

 from each other and from the eyes. 



Prothorax fully one-third wider than long, brown, with 

 a yellow middorsal band covering one-third its width, 

 parallel sided but diffuse and ill-defined laterally. 



Legs, pale brown. Wings subhyaline with brown veins. 

 There are two oblique crossveins in the apical space. The 

 tip of the subcosta lies some distance before the cord. 



