PE ELIDES. 143 



7. PERLA VENTRALIS. 



Fusca ; prothorax longitudine vix latius, vitta flava ; ales limpidce, 

 apud costam late flavce. 



Perla ventralis, Pictet, Hist. Nat. Neur. Perl. 164, 5, pi. 8, f. 8, 9. 

 Balkan. 



8. PERLA IMHOFFII. 



Lcetefusca ; prothorax non vittatus. 



Perla Imhoffii, Pictet, Hist. Nat. Neur. Perl. 166, 6, pi. 9, f. 9, 10. 

 Basle. 



Group 2. ISOGENUS. 



Nigra, vitta flava. Ala? macula apud stigma nebulosa ; vena 

 subcostalis accessoria valde ramosa et irregularis ; regionis sub- 

 marginalis pars terminalis venis transversis non divisa. Alae pos- 

 ticae regione anali magna, plica ta. 



Isogenus p., Newman, Ent. Mag. i. 415. Sexuura amborum alis 

 pariter repandis, pariterque abdomen tegentibus ; telo setis 

 duabus instructo. 



Nephelion, Pictet, Hist. Nat. Neur. Perl. 144, 3. 



Terminal part of the submarginal region without cross- veins ; 

 accessory vein of the subcostal vein much ramified and very irregu- 

 lar. Species with a black body, which has almost always the yellow 

 stripe, with the likeness of Dictyopteryx ; they are also characterized 

 by a blackish clouded spot on the side where the principal line of 

 the cross-veins terminates. 



9. PERLA NUBECULA. 



Caput macula flava. occipitali ; from omnino nigra ; prothorax 

 longitudine paullo latius, vitta flava ; alee anticce sordide hya- 

 lince, nubecula costali ultra medium fusca. 



Perla bicaudala, St. Farg. et Serv. Enc. Meth. Ins. x. 69, 1. Dum. 



Cons. Gen. Ins. pi. 27, f. 10. Pictet, Ann. Sci. Nat. xxviii. pi. 



6, f. 6, 7. Burm. Handb. Ent. ii. 878. 

 Perla nubecula, Pictet, Hist. Nat. Neur. Perl. 170, 7, pi. 9, f. 16. 



