1802.] 2!)1 



surface. A day later, its color ha.s become dull, it i.s more sluggish in its 

 movements, and is no longer capable of clinging to even a rough surface 

 with its feet, from which, before, it could with difficulty be detached. If 

 a box of earth be now furnished it, it at once thrusts in its head, and in a 

 brief space of time di.sappears beneath the surface, penetrating to the bot- 

 tom of the box where it constructs the cell in which it undergoes its pupa 

 and imago metamorphoses. 



The Cell measures 21 by 1| inches, and is of an elongate oval form, flat- 

 tened on the bottom of the box, with its broader end elevated at an angle 

 of about fifteen degrees; from this end the imago always makes its escape. 

 The cell is molded in general outline by the pressure of the body of the 

 larva, and afterwards worked into its precise shape and compactness of wall 

 by the stronger muscular force of the head. The entire inner surface of 

 the cell is covered with little pits made by the anterior portion of the head, 

 in which the impress of the mandibles is plainly seen. 



By the time that the cell is completed, a contraction in the length of 

 the larva, and a gradual approach in form to that of a pupa is apparent. 

 Five days after entering the earth, the skin, which has become shrivelled 

 and dry, separates at the dorsal line on the first segment, disclosing the 

 pupa, and very soon thereafter the operation of removing the skin com- 

 mences. By alternate extensions and contractions of the segments, the 

 skin is seized between them and drawn backward, forcing the head of the 

 pupa within the opening which enlarges by its extension across the second 

 segment, and down the central suture of the head-case. The skin having 

 been by this means loosened from the inclosed pupa, and partially with- 

 drawn, its removal is completed by means of the spine, in which the ab- 

 domen of the pupa terminates, which is thrust into the skin at various 

 points, and from the freedom of motion — both laterally and linearly — 

 which the abdominal structure allows it, accomplishes the work with ease 

 and rapidity. With this statement of the important part which the ter- 

 minal spine performs in this metamorphosis, those who have previously 

 looked upon the long, stout and bifurcated spine of the Bri/ocampidse, 

 simply as a curious appendage, may see in it an admirable provision for 

 overcoming the apparent difficulty of the removal of the skin from a pupa 

 roughened with granulations, thickly studded with teeth, and encircled on 

 each ring with an armature of spines. 



The Pupa, which is at first of an amber color, in the course of a few 

 hours changes to brown, although entirely excluded from the light. In 

 two or three days it becomes a very dark glossy brown, its wing cases tin- 



