Fig. 29.—A Moth, Saturnia pyri (S. Europe), with its Caterpillar, A; its Cocoon, B; Cocoon cut open to show Chrysalis, C; Adult insect, D.
The beetles, Coleoptera, are, like the butterflies, endlessly numerous. They are characterised by the striking difference in their two pairs of wings, of which the anterior pair is strong and horny, and forms, when at rest, a sheath which covers the thinner posterior pair of wings. The metamorphosis is complete in this group also. [Fig. 31] shows an example which is typical except in one respect—the adult form, namely, is one of the comparatively few instances of adult insects that live in water.
Fig. 30.—Nest of gregarious Caterpillar of a Moth, Hypsoides.
Fig. 31.—Development of an English Water-Beetle, Dytiscus. Grub; Pupa; Adult insect.>