The Life-History and Anatomy of Butterflie* 



A few species live gregariously during the period of hibernation, 

 constructing for themselves a shelter of leaves woven together 

 with strands of silk. 



Transformation.— The. larval or caterpillar stage having been 

 completed, and full development having been attained, the cater- 

 pillar is transformed into a pupa, or chrysalis. Of this, the third 

 stage in the life of the insect, we now shall speak at length. 



THE PUPA, OR CHRYSALIS 



The caterpillars of many butterflies attach themselves by a 

 button of silk to the under surface of a branch or stone, or 

 other projecting surface, and are transformed into chrysalids, 



Fig. 23. — Caterpillar of Anosia plexippus, undergoing 

 change into chrysalis: a, caterpillar just before rending of the 

 skin; b, chrysalis just before the cremaster, or hook, at its end 

 is withdrawn ; c, chrysalis holding itself in place by the folds 

 of the shed skin caught between the edges of the abdominal 

 segments, while with the cremaster, armed with microscopic 

 hooks, it searches for the button of silk from which it is to 

 hang (Riley). (Compare Fig. 24, showing final form of the 

 chrysalis.) 



which are naked, and which hang perpendicularly from the sur- 

 face to which they are attached. Other caterpillars attach them- 

 selves to surfaces by means of a button of silk which holds the 

 anal extremity of the chrysalis, and have, in addition, a girdle of 

 silk which passes around the middle of the chrysalis, holding it 

 in place very much as a papoose is held on the back of an Indian 

 squaw by a strap passed over her shoulders. 



The Form of Chrysalids.— The forms assumed by the insect 

 in this stage of its being vary very greatly, though there is a general 

 resemblance among the different families and subfamilies, so that 



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