364 PROCEEDINGS OP THE ACADEMY OP 



half of the penultimate. Wings subflavescent, the subcostal vein and its 

 accessory brown, the rest mostly luteous. 



Alar expanse ^ 2629 mill., $ 3540 mill. Length J 1 3| 4 mill., $ 46 

 mill. Four (j^, three 9 Allied to P. capitata, Pictet, bat distinct. In one $ 

 and one 9, the accessory subcostal of one wing is only one-branched. In $ 

 of this species the 5th abdominal segment is semicircularly elongated, so as to 

 conceal almost entirely the upcurving abdominal joints 6 8, and the 9th ven- 

 tral is entirely concealed by the 8th, which is large. 



Perla varians, n. sp. 'Fuscous. Head as wide as, or wider than the pro- 

 thorax in some specimens, with the usual divaricating carinas equal and 

 polished, and obscurely returning in the form of an inverted W ; epistoma 

 longer than usual, with a dilated puncture on each side ; occiput with a semi- 

 circular or transverse yellow or luteous spot, which is never longer than wide, 

 and sometimes extends to the sides of the head; beneath luteous; palpi and 

 antennae fu?cous. Prothorax nearly twice as wide as long, quadrangular, not 

 contracted behind, the sides straight, the angles acute before, scarcely rounded 

 behind, rugulose, with a yellow or luteous vitta in the middle, and a more or 

 less obvious submarginal luteous cloud on each side. Sternum luteous. Legs 

 luteo- fuscous, with coxae, trochanters and knees luteous. Abdomen with the 

 last joint, luteous ; venter obscurely marked with luteous on the disk and some- 

 times the tip. Setae fuscous, sometimes with a few basal joints luteous ; $ an- 

 tepenultimate ventral segment semi-oval behind, sometimes a little angulated 

 in the middle, almost entirely covering the penultimate segment. Wings sub- 

 hyaline ; veins of anteriors browD, with a small brown cloud on the anterior 

 part of the " arc," which is never entirely obsolete ; veins of posterior wings 

 partly luteous. 



Length to tip of wings 14 18 mill. Alar expanse 28 36 mil!. Length of 

 abdomen 5| 8 mill. It comes very near to P. postica, Walker, but that species 

 has the occipital spot hastiform, and no subcostal spot on the wings. Described 

 from eleven specimens. The species is remarkable for having almost always 

 a cross-vein behind the accessory subcostal vein and outside the "arc," so as 

 to form there a trapezoidal or pentagonal cell. Sometimes this cross-vein is 

 present in one wing in the same individual, and absent in the other; iu one 

 specimen there are on one side three additional subapical cross-veins, making 

 four altogether, thus approximating to Acroneuria, and none at all on the other 

 side. The accessory subcostal vein is incurved at its origin, and generally 

 appendiculated there ; and is further remarkable for sometimes throwing out 

 only one branch, sometimes as many as three, the wing being often normal on 

 one side and abnormal on the other. 



In the $ the 9th ventral segment is distinct, and never concealed by the 

 8th. In the $ the 7th abdominal segment is prolonged laterally much be- 

 yond the other abdominal segments, so as to partially cover the base of the 

 antepenultimate ventral. 



Perla decipiens, n. sp. Bright clay-yellow, sometimes verging on orange. 

 Head wider than the prothorax, with a square black spot enclosing the ocelli, 

 and a smaller round submarginal one before, which are sometimes almost con- 

 fluent, sometimes obscure fuscous, sometimes, but not often, obsolete ; the usual 

 divaricating carina is generally a little depressed in the middle of each branch 

 and scarcely returns backwards ; palpi and anteunae fuscous, the latter luteous 

 joints 2 8. Prothorax one-third wider than long, rugulose, quadrangular, its 

 sides straight, very slightly narrowed behind, anterior angles acute, posterior 

 ones scarcely rounded; fuscous or obscure, always with a narrow central yel- 

 low or luteous vitta ; meso- and meta-thorax more or less obscured with fuscous. 

 Legs clay-yellow, with a fuscous vitta above on the femora and tibiae, and the 

 tarsi fuscous. Abdomen sometimes a little varied with fuscous, especially 

 above, in one mature specimen entirely fuscous above and below. Setae hairy, 



[Sept. 



