APPLE LEAVES APHIS-LIONS, PUPA. 



81 



which are double the size of the larvae. 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 hide 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 antennae enclosed in separate sheaths. 

 The antennae -sheaths 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 curious 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 antennae globu- 

 lar, and Ckrysopa or the Golden-eyed flies, in which they are 

 short cylindrical. To these genera it is necessary to add a third, 

 resembling C/irysopa in most of its details, but instead of having 



(Assembly, No. 215. | 5 



