100 THOMAS SAY FOUNDATION 



Abdomen brown, lighter beneath, especially the ante- 

 rior portion. Tails brown, darker toward the tip, very 

 hairy. 



Male. Abdominal segments normal to the 7th which 

 only differs from preceding segments by a patch of 

 prickles on the dorsum either side of the middle line, the 

 dorsum of the 8th segment carries besides similar dense 

 patches of prickles a little triangular tubercle on the 

 apical margin, the 9th segment is concave posteriorly 

 upon the dorsum and little prolonged on the ventral side 

 underneath the 10th segment. The 10th segment is cleft 

 on the dorsum and the hind angles beside the cleft are 

 elevated in a pair of processes that are at first erect and 

 then sharply bent forward and approximated at their 

 tips, which stand opposed to the middle median tooth on 

 the apex of the 8th segment. Externally these genital 

 hooks are very hairy. 



Female. The subgenital plate of the female is an ill- 

 defined prolongation of the 8th sternite, triangular in 

 form, overlapping more than half the length of segment 

 9, conspicuously emarginate at the tip with the two lobes 

 beside the notch rather bluntly pointed and parallel or 

 incurving. A pair of small, brownish, oval spots mark 

 the sides of the 9th sternite. 



Distribution. — Kansas, Douglas County in July. Riley 

 County in September, Lawrence, June 23, 1919 (P. W. 

 Claassen). 



Perla languida, new species. 



(Plate 13, figs. 5, 7; plate 19, figs. 18, 19, 20.) 



Length to wing tips, male, 18 mm.; female, 28 mm. 

 Expanse, male, 23 mm. ; female, 43 mm. 



Color brown and yellow, mostly pale. Head yellow 

 across the rear and around the eyes. A brownish spot 

 fills the ocellar triangle and extends forward and laterally 

 behind the obscure M-line to the roots of the antennae, 

 and a brownish cloud occupies the middle of the clypeus. 

 Antennae brownish yellow, paler along the base of the 

 fiagellum. Palpi yellow. Ocelli more than twice as large 

 in the male as in the female, the paired ones more than 

 twice as large as the median, and separated by little more 

 than their diameter (three times as far apart in the fe- 

 male) ; more than twice as far from the compound eyes. 



Prothorax subrectangular, hardly as wide as head, nar- 

 rowing a little to rearward. Front and hind margins are 

 convex, especially the former. The middorsal suture may 

 be either brown or yellowish. The embossed markings are 



