144 PERLIDES. 



Isogenus uebecula, Newm. Ent. Mag. i. 415. Steph. III. Brit. Ent. 

 Hand. vi. 137, 1, pi. 31, f. 4. 



a. England. 



10. PEELA FRONTALIS. 



Frisco, ; caput macula flava occipitali ; frons macula V-flava ; 

 prothorax longitudine paullo latius, vitta flava ; alee antica 

 hyalince, fusco tinctce^ nubecula costali ante medium vix con- 

 spicua fusca. 



Isogenus frontalis, Newm. Ent. Mag. v. 178. Mag. Nat. Hist. iii. 



85. 



Perla bicaudata, Kirby, Faun. Bor. Amer. Ins. 252. 

 Perla frontalis, Pictet, Hist. Nat. Neur. Perl. 172, 8, pi. 8, f. 10, 1 1. 



a c. Trenton Falls. Presented by the Entomological Club. 

 d. St. Martin's Falls, Albany River, Hudson's Bay. Presented by 

 G. Barnston, Esq. 



11. PEKLA POSTICA. 



Atra, nitens ; caput thorace vix latins, maculis tribusflavis ; pro- 

 thorax flavo vittatus, antice bicornis ; alee subhyalina. 



Black, shining : head a little broader than the thorax, with a 

 yellow triangular spot on the hind-border, and a pale yellow spot on 

 each side in front of the antennae : prothorax very rugulose, with a 

 yellow stripe along the longitudinal furrow, produced into an acute 

 angle or short horn on each side by the fore-angle, hardly broader 

 in front ; sides almost straight ; angles rather sharp : wings subhy- 

 aline ; veins black; external basilar areolet with five transverse 

 veins ; terminal areolet with four transverse veins ; submediau areo- 

 let with six or seven ? transverse veins. Length of the body 5 

 lines ; of the wings 16 lines. 



a. Mackenzie River, Arctic America. Presented by Sir John 

 Bichardson. 



12. PERLA OLIVACEA. 



Piceo-nigra ; caput thorace vix latius, macula triangulari margine- 

 que postico Jlavis ; prothorax rugulosus, vitta flava, lateribui 

 rectis, angulis sat acutis ; alee subcinerece. 



Perfa olivacea, Barnston,, MSS. 



