NATURAL SCIENCES OP PHILADELPHIA. 363 



\\ Perla. Subgenus Acronedria. 



Acroneuria rupinsitlensis, n. sp. 9 Obscure luteous. Head broader than 

 the prothorax, bright testaceous, the epistotna scarcely excavated ; a transverse 

 line at tip, a raised discal line in the form of an M with its sides divaricate, 

 and a subobsolete basal line commencing at the eyes and curving backwards, 

 fuscous ; the usual two interocular tubercles oval, oblique ; palpi fuscous ; 

 antennae fuscous, with the joints from 2 to about 7, and the first joint beneath 

 luteous. Prothorax nearly twice as wide as long, subcordate, anterior and 

 posterior angles acute, excurved, the sides Dearly parallel before the mid- 

 dle, gradually contracted behind the middle, the prothoracic episternum not 

 thrust underneath as in other Perlae, but distinctly visible behind from above, 

 so as to give at a distance a quadrangular appearance to the whole prothorax ; 

 the middle longitudinal stria acute, surface rugulose, luteo-fuscous with fuscous 

 rugae. Prosternum and anterior half of metasternum bright luteous. Legs 

 luteous, with obscure fuscous vittae. Abdomen and venter with obscure fuscous 

 markings; abdominal setae luteous, annulate with fuscous towards their tips, 

 not pilose except under the lens ; 9 antepenultimate ventral segment regularly 

 rounded, so as at the centre, where it is slightly emarginate, to cover one half 

 of the penultimate segment, with a subobsolete linear transverse tubercle before 

 the apex. Wings subhyaline ; veins of anterior wings mostly brown, of pos- 

 terior mostly clay-yellow ; the vein accessory to the subcosta in the anterior 

 wing throwing out four branches, one of which occasionally becomes bifid ; in 

 one specimen the veins on the posterior apical submargin are obsolete ; from 

 four to thirteen subterminal cross-veins. 



Length to tip of wings 9 39 m ^- Alar expanse 9 64 f * m ^- Length of 

 abdomen 9 about 9 mill. The J 1 I have not yet met with. Described from 

 two specimens. 



Differs from abnormis in the greater relative width of the prothorax, in its 

 sides not being straight, and its not having any luteous dorsal line. Also in the 

 greater extension of 9 antepenultimate ventral segment, and its having a sub- 

 terminal tubercle. From ruralis and arida it differs in the accessory subcostal 

 being 4 (not 5 or 3) branched. 



Perla. Subgenus A. Accessory vein two-branched ; three ocelli. 



Perla flavescens, n. sp. Clay-yellow. Head a little broader than the 

 prothorax, bright clay-yellow, with a divaricating unequal carina proceeding 

 from each side of the anterior ocellus to the anterior sub-margin, where there is 

 sometimes a large dilated puncture on 6ach side ; a large quadrangular fuscous 

 spot at tip, and another at the base, from which last issue two wide branches nearly 

 attaining the base of the antennae, the two spots sometimes almost confluent ; 

 palpi fuscous ; antennae fuscous, second joint luteous, third to about the eighth 

 luteous annulate with fuscous ; the under side of the head is more or less fuscous 

 at base. Prothorax rugose, entirely fuscous, its breadth exceeding its length by 

 one-half, considerably narrowed behind, with its sides straight, its anterior 

 angles acute, and its posterior ones a little rounded ; meso- and meta- thorax 

 brown-black, polished, with clay-yellow margins. Legs clay-yellow, femora 

 sometimes vittate beneath, and always strongly above, with brown-black, a 

 triangular spot at their tips confluent with the upper vitta, and the posterior 

 femora fuscous at base; tibiae vittate above with fuscous; tarsi fuscous. 

 Sternum fuscous almost entirely. Abdomen 9 sometimes fuscous only at the 

 sides and tip, sometimes with the base of each segment fuscous ; abdomen <^ 

 with the 3 or 4 basal segments clay-yellow and the rest fuscous ; venter in both 

 sexes obscure luteou3, banded with fuscous; sette brown-black, pubescent; 

 $ last few abdominal segments are curved upwards, and the last, which is small 

 and only visible at the sides, triangularly open above ; 9 antepenultimate 

 ventral segment is semicircularly produced in the middle, so as to cover one- 



1862.] 



