NATURAL SCIENCES OP PHILADELPHIA. 



367 



Sometimes in my species the head is pure yellow, with only the eyes and 

 ocelli black. The abdomen is sometimes pure yellow, sometimes with a wide 

 fuscous band in the middle, sometimes entirely fuscous. But the prothoracic 

 vittcE are always distinct. The $ has the last abdominal joint small, internal. 



The $ antepenultimate ventral segment is triangularly extended so as to 

 completely cover the penultimate. The 9th $ ventral is apparently concealed 

 by the 8th, which is very large and triangularly extended at tip, with no ap- 

 pearance of any suture. 



Length to tip of wings 11 14 mill. Alar expanse 21 27 mill. Length of 

 abd. 3 4 mill. Twenty specimens. 



Chloroperla brunnipennis, n. sp. Brown-black. Head much wider than 

 the prothorax ; ocelli three ; epistoma generally luteous ; antenna? luteous at 

 base. Mouth, base of abdomen, and all beneath, generally obscure luteous. 

 Prothorax rather wider than long, its sides straight, contracted behind, its 

 angles slightly rounded. Setae luteous at base, sometimes all but their tips 

 luteous. Antepenultimate segment 9 venter covering the penultimate. 

 Legs luteous, femora with a broad median black band, sometimes inter- 

 rupted beneath, especially in the front legs ; tibia black on their basal half, 

 sometimes luteous beneath, especially in the front legs. Wings all brownish, 

 the costa yellowish ; veins the color of the wing; front wings with a streak be- 

 tween the postmedian and postcostal veins, and the region of the origin of the 

 accessory subcostal, hyaline. 



Alar expanse 16 21 mill. Length abd. 3\ 4 mill. Two ^ one 9- 



Chloroperla nana, n. sp. Differs from the above in size, in the head being 

 immaculate above and below, and in the prothorax being one-half wider than 

 long, its angles rounded, and with a broad, median, luteous vitta. The hya- 

 line streaks on the wings are absent. 



Length to tip of wings 6| mill. Alar expanse ll mill. Abd. 2 mill. One 

 9? specimen. 



Isopteryx cydippe, Newman ! (= Perla imbecilla, Say?) Capnia minima? 

 Newport. T^niopteryx fasciata, Burm. ! (= T. frigida, Hagen ?) Nemoura 

 completa, Walker. 



EPHEMERINA. 



(Anterior tarsi always five-jointed ; the others generally five-jointed, but four- 

 jointed in Ephemera and Cloe.) 



Cross-veins numerous ; 

 costal cross-veiDS nu- 

 merous, robust, regu- 

 lar. (Wings 4, hind 

 wings wide with nu- 

 merous veins; very 

 few short, terminal 

 isolated veinlets at 

 the tip? of any of the 

 wings.) 



1862.1 



Eyes cf contiguous, 

 simple. (Interme- 

 diate seta, when 

 present, rudiment- 

 al.) 



Eyes (J contiguous, 

 double. (Three sub- 

 equal setae both in 

 imago and subim- 



ago.) 



Eyes (J not contigu- 

 ous, simple ; inter- 

 mediate 8eta,when 

 present, short or 

 rudimental. 



Eyes (J remote, sim- 

 ple ; three long se- 

 ta:, subequal in im- 

 ago, equal iu sub- 

 imago. 



' Firsi, tarsal joint longer 

 than the second, except 

 in anterior (J tarsus, 

 where they are equal. 

 First tarsal joint always 

 longer than the second. 

 First tarsal joint shorter 

 (. than the second. 



1 



^ Bjetis, subgenus A. 



J 



I B^tis, subgenus B. 



> B.ETIS, subgenus C. 



POTAMANTHUS. 



Legs all short ; intermedi 

 ate seta short. 



Legs all short, except cf 

 anterior legs ; intermedi 

 ate seta rudimental. 



Legs all long; no interme- 

 diate seta. 



\ Palinciema, subgenus A. 

 I Palingenia, subgenus B. 

 | Palinuema, subgenus C. 



f 



EPHKMK3A. 



