The subjects to be discussed in this chapter are of the highest interest, but are treated by me in an imperfect and fragmentary manner.

We are, however, here concerned only with sexual selection.

Throughout this great division of the animal kingdom, as far as I can discover, secondary sexual characters, such as we are here considering, never occur.

With insects of all kinds the males are commonly smaller than the females; and this difference can often be detected even in the larval state.

The bright colours of many butterflies and of some moths are specially arranged for display, so that they may be readily seen.

The male of the Cottus scorpius, or sea-scorpion, is slenderer and smaller than the female.

Almost all male birds are extremely pugnacious, using their beaks, wings, and legs for fighting together.

Birds possess acute powers of observation.

The truth and importance of the principle of inheritance at corresponding ages need not here be discussed, as enough has already been said on the subject.

Parmenides by Plato, is part of the HackerNoon Books Series. Read this book online for free on HackerNoon!