PERLA. 21 



arcuated one; beneath yellow; wings obscure, veins fuscous, im- 

 marginate. 



"It varies very much in coloring, being generally entirely yellow 

 beneath, and sometimes upon the tergum. The thorax has some- 

 times a yellow dorsal line, and sometimes a black one." — Say. 



Length to tip of wings ? 30 millim. ( u more than one inch"). 

 Male smaller. 



Hob. Ohio River : "common in May" (Say). Unknown to me. 



Perhaps a unique male from Washington (Osten Sacken) be- 

 longs to this species. 



11. P. lurida ! 



Perla lurida Hag.! 



Testaceous, varied with yellowish ; head hardly broader than the 

 prothorax, yellowish, a broad fuscous stripe upon the middle excised 

 in front and drawn out into a semilunar form posteriorly ; antennae 

 testaceous ; prothorax quadrangular, narrower posteriorly, testa- 

 ceous, rugulose, sides a little incurved, anterior angles acute, pos- 

 terior ones a little rounded ; feet testaceous, knees fuscous, under- 

 neath yellowish ; body beneath yellowish, setae testaceous-yellow, 

 base of the venter pale yellow ; antepenultimate ventral segment a 

 little produced, triangularly emarginate in ^the middle ; wings tes- 

 taceo-hyaline, veins fusco-testaceous. (Female.) 

 • Length to tip of wings 33 millim. 9 Alar expanse 62 millim. 



Hah. New Orleans (Pfeiffer). 



12. P. lycorias ! 



Perla lycorias Newm. Mag. Nat. Hist. ser. 2, III, 85. Pict. Perl. 214. 

 Walk. Catal. 152, 40. 



Testaceous-yellow ; head broader than the prothorax, orange- 

 yellow, a transverse, trilobed, brownish-testaceous band ; anteriorly 

 and posteriorly clouded with fuscous; antennae brownish-testaceous, 

 base yellowish, first articulation brownish-black ; prothorax quad- 

 rangular, hardly narrower posteriorly, sides straight, angles acute ; 

 its color orange-yellow, with fuscous rugulae, a middle line brown- 

 ish-black ; feet testaceous, knees and the tibiae externally, fuscous ; 

 beneath yellowish, setae fusco-testaceous, pilose; £ , last ventral 

 segment larger, rounded, furnished with a transverse, ovate, flat, 

 polished tubercle ; 9 , antepenultimate segment with an elliptical 

 middle lobe ; wings subhyaline, veins fusco-testaceous. 



