785 
No. 145.] 
which are double the size of the larvse. It is like a full grown 
hen hatching from an ordinary sized egg. 
It requires five or six hours for the New-York Golden-eye to 
spin so much of its cocoon as to h ; de itself from view. The 
threads of which it is composed are of a white color, and the 
little paper-like ball in its centre is scarcely the tenth of an inch 
in diameter. Within this the insect changes to a pupa of a pale 
green color, with large hemispherical eyes, and with each of the 
legs, the wings and the antennse enclosed in separate sheaths. 
The an ennje .'■heaths show the bead-like joints of these organs 
very distinctly. They stand out in strong relief upon the sur¬ 
face, passing above the eyes and along the sides of the thorax, 
and on the outer surface of the wing-sheaths near their anterior 
margin to their tips, where the remainder of their length is coiled 
and doubled together in a singular and cuiious manner. 
These insects lie through the winter enclosed in their cocoons. 
Some of the species, however, have two generations annually, and 
these remain in their pupa state in the summer season about a 
fortnight. M. Andouin informed Mr. Westwood that they escape 
from their cocoons by means of a slit made in a spiral direction 
at one end. But this certainly is not their usual manner of open¬ 
ing their cocoons. One side of the cocoon where it is globular, 
and one end where it is oval, is cut smoothly off, so as to form a 
little lid, which commonly hangs to the cocoon by some of the 
loose exterior threads, which serve as a hinge to retain it in its 
place. Through the opening thus made the pupa crawls out of 
its cocoon before it casts its skin to become a perfect fly. 
Of this family of insects, which are rendering us such important 
services, our American species are somewhat numerous. Only 
two of these, I believe, have as yet been named and described. I 
therefore present herewith descriptions of most of the species 
which are known to me. These pertain to two genera, Hemerobius 
or the Lace-winged flies, having the joints of the antennse globu¬ 
lar, and Chrysopa or the Golden-eyed flies, in which they are 
short.cylindrical. To these genera it is necessary to add a third, 
[Assembly, No. 145.] 50 
