448 Mr. Newport on the Anatomy and 
nosa, they agree with both in every particular, so that I have no doubt of 
their identity. The species appears to have a wide geographical range, 
from Philadelphia southward as far north as Canada; and probably is 
the common species of the North American continent. The larva and 
pupa of this species have also been taken by Mr. Barnston, and specimens 
of them, presented by that gentleman, are now in the cabinets of the Bri- 
tish Museum. As they have not hitherto been described, I may state 
generally that in size, colour and markings the pupa closely resembles that 
of the European species, Perla bipunctata, Pictet*. The larva is smaller, 
and of the same colour as the pupa, but is less distinctly marked. It is 
yellow with black bands. Its head is flattened and subtriangular, with the 
eyes black, depressed, and placed on the upper lateral surface, and on the 
front there are three minute black points in the place of the future ocelli. 
The antenne are setaceous, yellow, and have about ninety articulations. 
The labrum is short, wide, and of a brown colour, and the front has two 
transverse, waved brown bands. The prothorax is suboval, flattened, with 
two indistinct black marks on the upper surface, encircled with a black band. 
The meso- and metathorax are transverse, subquadrate, with the posterior 
angles and margin dilated. Each segment has an indistinct subtriangular 
mark in the middle, encircled with a broad black band. The abdomen is 
yellow, with the posterior margin of each segment on the dorsal surface dark 
brown, or black. The caudal styles are tapering, yellow, and with about 
fifty articulations. The ventral surface of the body is entirely yellow, and 
there are small branchiz on the first and second abdominal segments, but 
not on the ventral surface of the thoracic. The legs are compressed, with the 
thighs dilated and the tibize densely ciliated. 
The pupa differs from the larva in its greater size, darker colour and mark- 
ings, and in the elongation of the angles of the meso- and metathoracic seg- 
ments into long triangular rudiments of wings, which, in addition to the 
Wk band at the base of each, have also another at their apex. The thighs 
e dilated as in the larva, and have two brown bands, and the tibiæ are also 
ciliated for swimming. It is entirely without external branchiz. 
The habits of this species have been carefully observed by Mr. Barnston. 
* Loc. cit. pl. 11. 
