144 PERLIDES. 



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

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



a. England. 

 h. -? 



10. Peela frontalis. 



Fusca ; caput macula flava oceipitali ; frons macula V-Jlava ; 

 prothorax longitudine paullo latius, vltta jlava ; alee antica 

 hyalin(E,fusco tinctce, riubecula 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, 11. 



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. Peela postica. 



Atra, nitens ; caput thorace vix latius, maculis trihus jiavis ; pro- 

 thorax flavo vittatus, antice hicornis ; alcB suhhyalince. 



Blaclv, 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 



Richardson. 



12. Perla olivacea. 



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

 que postico jiavis ; prothorax rugulosus, vitfa flava, latenbus 

 rectis, angulis sat acutis ; alee subcinerecc. 



Perla olivacea, Barnston, 3ISS. 



