. The butterfly book; a popular guide to a knowledge of the butterflies of North America. Butterflies -- North America. Fig. 5.—Pupa of Tclea polyphemus. (Riley.) encased in hard chitinous rings and sheathings. As a measure of protection during this stage, the insect, before transforming into a pupa, descends into the earth, and forms there a cell at a greater or lesser depth beneath the surface, or else weaves a cocoon of silk about its body. In some cases the transformation takes place at the surface of the earth under leaves or under fallen branches and the loose bark of trees. In almost al
. The butterfly book; a popular guide to a knowledge of the butterflies of North America. Butterflies -- North America. Fig. 5.—Pupa of Tclea polyphemus. (Riley.) encased in hard chitinous rings and sheathings. As a measure of protection during this stage, the insect, before transforming into a pupa, descends into the earth, and forms there a cell at a greater or lesser depth beneath the surface, or else weaves a cocoon of silk about its body. In some cases the transformation takes place at the surface of the earth under leaves or under fallen branches and the loose bark of trees. In almost all such cases there is apparently an at- tempt, though often slight, to throw a few strands of silk about the body of the caterpillar, if only to hold in place the loose material amidst which transformation is to occur. The forms assumed in the pupal stage are not as remarkably diversified as in the larval or imaginal stages. The pupae of moths are generally brown or black in color, though a few are more or less variegated. The bright golden and silvery spots which ornament the pupae of many species of butterflies, causing them to be called chrysalids, are seldom, if ever, found. While the change into a pupa might at first sight appear to the superficial observer to be disadvantageous because of the loss of motion and the imprisonment within narrow bounds, it neverthe- less distinctly marks a progression in the life of the creature. The pupal case contains within it the moth, as may easily be ascertained by a care- ful dissection made in the very earliest period after the change has occurred, and which becomes very evident at a later time when the period of the pupal life is drawing to its close. In the cocoon or in the cell in which pupation has taken place will always be found the exuviae, or the larval skin, etc., of the caterpillar, which have been cast off. When the time comes for the perfect insect to emerge from the pupa, nature has provided methods by which escape from
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