. Zoology for high schools and colleges. Zoology. METAMORPHOSIS OF INSECTS. 333 Most caterpillars moult four pr five times; at each moult the outer layer of the skin is cast ofE, the new skin arising from the hypodermis, or inner layer of the in- tegument. The skin opens on the back behind the head, the caterpillar drawing itself out of the rent. In the change from the caterpillar to the chrysalis, there are re- markable transformations in the muscles, the nervous, digestive, and circulatory system, inducing a change of form, external and internal, characterizing the different stages in the me
. Zoology for high schools and colleges. Zoology. METAMORPHOSIS OF INSECTS. 333 Most caterpillars moult four pr five times; at each moult the outer layer of the skin is cast ofE, the new skin arising from the hypodermis, or inner layer of the in- tegument. The skin opens on the back behind the head, the caterpillar drawing itself out of the rent. In the change from the caterpillar to the chrysalis, there are re- markable transformations in the muscles, the nervous, digestive, and circulatory system, inducing a change of form, external and internal, characterizing the different stages in the metamorphosis. While the changes in form are comparatively sudden in flies and butterflies, the steps that lead to them are gradual. How gradual they are may be seen by a study of the metamorphosis of a bee. In the nest of the humble or honey bee, the young may be found in all stages, from the egg to the pupa gayly colored and ready to emerge from its cell. It is difficult to indicate where the chrysalis stage begins and the larva stage ends, yet the metamorphosis is more completeânamely, the adult bee is more unlike the larva, than in any other insect. Besides the normal mode of de- velopment, certain insects, as the ^e- of the Louse. â ^ ' ' om, eeronsmembrani-d&, amnion; plant-louse (Aphis), the bark-louse <m. antennae; vk forehead.âAfter (Coccus), the honey-bee, the Po- listes wasp, the currant saw-fly (Nematus), the gall-flies, and a few others, produce young from unfertilized eggs. Certain moths, as the silk-worm moth (Bomhyx mori) and others, have been known to lay unfertilized eggs from which caterpillars have hatched. This anomalous mode of repro- duction is called parthenogenesis, and fundamentally is only a modification of the mode of producing young by budding which is universal in plants, and is not unusual, as we have. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - co
Size: 1150px × 2173px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectzoology
