File:Insect transformations (1831) (14577287619).jpg

Identifier: insecttransforma00inrenn (find matches)
Title: Insect transformations
Year: 1831 (1830s)
Authors: Rennie, James, 1787-1867
Subjects: Insects
Publisher: Boston : Lilly & Wait
Contributing Library: University of Pittsburgh Library System
Digitizing Sponsor: Lyrasis Members and Sloan Foundation

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ack of the head andshoulders, and, through the opening, first the headand then the legs of the perfect fly make their exit,whilst the empty slough of the legs continues fixedin its place. After this first part of the process isaccomplished, it hangs down its head and rests fora space, as if exhausted by previous exertion, orrather to allow the newly excluded parts to dry andbecome more firm. It next erects itself, and layinghold of the upper part of the slough with its teet,pulls the parts still enveloped further out, thencreeping forward by degrees, it disengages the en-tire body, and again rests .^or a time immovable.The wings now begin to expand thcmsolvcs, andtheir plaits and folds become gradually smooth.The body, also, becomes insensibly larger andlonger, and the limbs acquire their just size and pro-portions. While the wings are undergoing thisoperation of drying and expanding, the insect takescare to keep them from coming into contact with the EXPANSION OF PEUFECT INSECTS. 337
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A, the dragon-fly, beginning to escape from the pupa; a, the flv; 4,ihepupa case. B, the process lunher advanced; r. the flv; d. the pupacase. C, the fly nearly free, an.l forming an arch; ., the flv;/, thepupa case. D, the fly bending back its bodv.so as not to obstruct theexpansion of the wings. VOL. VI. 29 338 INSECT TRANSFORMATIONS. body, by bending itself into the form of a crescent;for if they were obstructed, whilst wet, they could notafterwards be set to rights. All these changes are perfected, according to Swam-merdam, by the force of the circulating fluids and theair, impelled by respiration, a fact of which, we think,there cannot be any doubt. It is very seldom, how-ever, that we can surprise insects at the precise mo-ment of their transformation, as it is for the most partvery speedily accomplished, for the whole of the pre-ceding evolutions are usually completed in ten or fif-teen minutes. It happened by mere chance, saysSwammerdam, that I observed them for the first time

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