The hardened forewings of Beetles, serving as sheaths for the membranous hind-wings, which constitute the true organs of flight.

The young animal undergoing development within the egg or womb.

The study of the development of the embryo.

Peculiar to a given locality.

A division of the class Crustacea, having all the segments of the body usually distinct, gills attached to the feet or organs of the mouth, and the feet fringed with fine hairs. They are generally of small size.

The earliest of the three divisions of the Tertiary epoch of geologists. Rocks of this age contain a small proportion of shells identical with species now living.

Insects allied to the Mayfly.