PERLIDES. 155 



furrow, broader in front, straifj^ht on each side; hind anjjles rounded ; 

 fore an<^lc.s sharp: \vini,^s dark hrown ; veins hhick ; external basilar 

 areolel with ten transverse veins ; terminal areolet with twu trans- 

 verse veins ; subinedian areolet with six transverse veins. Lenf^th 

 of the body i") lines ; of the win<;s 10 lines. 

 a. Venezuela. From Mr. Dyson's collection. 



Sub-^roup 2. 



Species mediocres. Prothorax fuscus, rugosus, lateribus rectis. 

 \\x omnino hyalinae et limpidae, venis fuscis. 



Species of moderate size: prothorax with straight sides, brown, 

 rugose : wings quite transparent and colourless, with brown veins. 



47. Perla vitripennis. 



I'erla vitripennis, Burm. Handh. Ent. ii. 880, 10. Pictet, Hist 

 Nat. Near. Perl. 224, 28, pi. 20, f. 1,2. 



Germany. 



48. Pebla bicolor. 



Perla bicolor, Burm. Handh. Ent.' ii. 880, 9. Piclet, Hist. Nat. 

 Xeur. Perl. 22(), 29, pi. 20, f. 3, 4. 



France, Germany. 



49. Perla terminalis. 



Nigra, xubtus lutea ; caput thorave vix latius, margine antico late- 

 rihusffue luteis ; antennte uigne ; prothorax subrugulosus, an- 

 tice jiaullo latins, subtnarginatus^ subsulcatus, lateribus rectis, 

 angulis acutis ; altc hgalimc. 



Black, luteous beneath : head vtry little broader than the tho- 

 rax, luleous on each side and in fiont: antennjp l)lack, testaceous 

 idwards the base : ])rotluirax niinuti'ly nigulose, a little l)roader in 

 front, with a slight border and a slight middle furrow ; sides straight ; 

 angles sharp: wings hyaline ; veins blackish brown ; external basi- 

 lar areolet with seventeen transverse veins ; terminal areolet with 

 four transverse veins ; terminal part nf the submaiginal areolet with 

 no transverse veins ; submedian areolet with seven transverse vein.>. 



