Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges . nes. The muscles, which beforewere uniformly distributed, are now gathered into limbs are elongated, and wings spring forth from thethorax. More active motions then reappear in the digestiveorgans, and the animal, bursting the envelop of its chrysalis,issues in the form of a winged moth. § 552. The different external forms which an insect may assume is well illustrated by one i f Fig. 369. which is unfortunately too well known
Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges . nes. The muscles, which beforewere uniformly distributed, are now gathered into limbs are elongated, and wings spring forth from thethorax. More active motions then reappear in the digestiveorgans, and the animal, bursting the envelop of its chrysalis,issues in the form of a winged moth. § 552. The different external forms which an insect may assume is well illustrated by one i f Fig. 369. which is unfortunately too well known in this country, namely, the canker-worm (fig. 369). Its eggs are laid onposts and fences, or upon the branchesof the apple, elm, and other are hatched about the time thetender leaves of these trees begin tounfold. The caterpillar («) feeds on .the leaves, and attains its full growth at the end of about fourweeks, being then not quite an inch in length. It thendescends to the ground, and enters the earth to the depth of * In the raising of silk-worms this period is not waited for, but theanimal is killed as soon as it has spun its METAMORPHOSES OF AKTMALS. 355 a
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1870
