1863.] 
187 
perfectly constant character to separate the two species. In both the 
shape of the prothorax is variable, and not as sharply contrasted one 
with the other as in the typical specimens, though there is a sepa¬ 
rating limit which neither transgresses. In one % and one 9 ahnormis 
the sides of the prothorax are exactly parallel, in the others a little 
convergent behind, as described. Again, in the same % ahnormis the 
dorsal line of the prothorax is as dark as any part of it; in all the 
others % 9 it is as pale as any part of it; in all 5 rupinmlensis % 9 
the dorsal line of the prothorax is as dark as any part of it. I can 
perceive no % character separating the two species, the S 'S of both 
having the same glabrous, transversely oval, subterminal tubercle on 
the eighth or what is apparently the last ventral joint, except that 
in the anomalous "S ahnormu already twice referred to, this tubercle 
is smaller. Consequently S riipinsulends can only be distinguished 
from % abnormiH by the comparatively greater breadth of the pro¬ 
thorax and its approximating more or less to the cordate form. In 
abnormisi the number of subterminal cross-veins in the front wing, 
exclusive of the “arc,” is 2—12, and in rupinsulensls 1—II, there 
being sometimes in the former a ditference of 4, and in the latter a 
difference of 1 cross-vein between the right and left wing. The dimen¬ 
sions, judging from the eye, are the same. 
All my specimens of abnormis agree pretty closely with the diag¬ 
nosis in the Synopsis, with the variations noted above. Dr. Hagen 
does not say in what respect my abnormis differs from the specimen re¬ 
ceived from Illinois and referred by him to abnormis^ and it is useless 
therefore to speculate on the subject. Judging from the long list of 
synonyms in the Synopsis, either several species are there confounded 
together, or it must be a more polymorphic species even than I have 
found it to be. 
Chloroperla fumipennis {~Perla fumipennis Walsh.) % Shining brown-black. 
Head brighter obscure luteous, with a large, round, shining, black spot enclos¬ 
ing the ocelli, which are only two in number. Antennae luteous on their basal 
i. Thorax scarcely wider than long, its sides straight and a little convergent 
behind, its anterior angles rounded and its posterior angles much rounded. 
Abdominal seta luteous on its basal i. Legs dull luteous, widely or narrowly 
vittate above with fuscous on the femora and tibiae: tarsi fuscous. All four 
wings equally tinged with fuscous, the front wing with a hyaline streak on the 
discal side of the origin of the accessory subcostal vein, and another between 
the postmedian and postcostal veins, and with their costa dull luteous; postcos- 
tal cross-veins 1—f; veins in all four wings fuscous. Alar expanse 16-^—-17 mill. 
