Page:Popular Science Monthly Volume 53.djvu/679

Rh paling, drawing together and permanently closing the head opening. It reverses its position in the case, so that the head is where the tail used to be—pointed toward the posterior or unattached end—and envelops itself in a soft silken cocoon of a yellowish color; allowing itself to hang perpendicularly, head downward, it awaits the pupal sleep.

From the facts just stated it need hardly be said that, when the time arrives, the perfect insect emerges from the posterior portion of the tube. At this particular time the male pupa becomes endowed with the power of stretching out its segments, to enable it to work its way out of the extremity. Through the opening of the posterior end it pushes the anterior half of its length, by a slight elongation and contraction of the body, which, with the assistance of a transverse series of minute sharp spines or hooks, directed backward, on some of the •segments, is in this way forced out head foremost, in like manner as the pupæ of the goat moths and the large swifts are made to emerge from timber and the earth when the moth is ready to escape. The pupæ are prevented from being thrust entirely out of the case by two strong anal hooks. After the issue of the imago the segments remain in their stretched-out condition; cases having belonged to males are often seen with the empty pupa skin sticking rather more than half out of the lower aperture, hanging head downward, as left by the moth.

The males of these moths are swift fliers, of extraordinary activity, dashing themselves wildly, almost to pieces, among the branches of the trees. A fiery little creature has no sooner arisen from his pupal slumber than he begins his violent fluttering, and as the wings are delicate in structure, in many instances nearly transparent, his beauty has generally disappeared before the entomologist can secure him; therefore specimens in good order are rare in collections.