Elements of biology, with special Elements of biology, with special reference to their rôle in the lives of animals elementsofbiolog00buch Year: 1933 358 ELEMENTS OF BIOLOGY Insect Types. The number of species of insects is far greater than that of all other animals taken together. Various authorities recognize nineteen different orders of insects, the order characters being wing differences, differences in mouth parts, and differences in number of stages in their life cycles, that is, in metamorphosis. According to the number of stages in their development, insects are divided into two group
Elements of biology, with special Elements of biology, with special reference to their rôle in the lives of animals elementsofbiolog00buch Year: 1933 358 ELEMENTS OF BIOLOGY Insect Types. The number of species of insects is far greater than that of all other animals taken together. Various authorities recognize nineteen different orders of insects, the order characters being wing differences, differences in mouth parts, and differences in number of stages in their life cycles, that is, in metamorphosis. According to the number of stages in their development, insects are divided into two groups, insects of incomplete metamorphosis, and FIG. 213. FIG. 214. Figs. 213 and 214.—A common bug and a common beede, showing the difference in the position of the wings and wing covers when at rest. insects of complete metamorphosis. Insects of incomplete meta- morphosis pass through three stages in development, namely, egg, nymph, and adult. Insects of complete metamorphosis pass through four stages, egg, larva, pupa, and adult. In insects of incomplete metamorphosis, the nymph and adult, and in insects of complete metamorphosis the larva and usually the adult, feed. Nymphs, larvae, and adults are therefore the stages that may be economically important because of damage to crops, trees, and other property of value. Uninformed observers frequently regard any insect as a bug, but bugs are in fact only one order of insects. The bugs, order Hemip-
Size: 1208px × 1656px
Photo credit: © Bookworm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
