Exceedingly multifarious are the ways in which insects thus provide for the future of young they will never see. _Antherophagus_ lives in flowers, and is believed to seize with its mandibles humble bees, which then unwittingly bear the parasitic beetle to the nests in which alone the larvæ have been found. The larvæ of our common oil-beetle (_Meloë_) are parasitic on the bee, _Anthophora_. It deposits its ten thousand eggs without observable discrimination; but the active young larva instinctively seizes and attaches itself to any hairy object. Thousands must go astray. They have been found on hairy beetles, flies, and bees of the wrong genus. Some, however, become thus attached to the one suitable species, and are conveyed by the _Anthophora_ to her nest, where they promptly eat the egg she lays. It is not difficult to picture to one’s self how this incompletely evolved instinct might be further perfected by natural selection, through the survival of those females which laid their eggs in the haunts of the bee-host. And such an advance in instinctive behaviour is seen in another and rarer beetle--_Sitaris_. Her eggs are laid in August near the entrance to a nest of the _Anthophora_. In September they hatch to form larvæ, which hibernate in groups till the following spring. Then they become active (Fig. 13, A), and attach themselves to hairy objects. Being near the _Anthophora_ nest, there is an increased chance of their fastening upon this bee. The chance is still far from good, for if this were so, we should not find that the _Sitaris_ laid as many as two thousand eggs. Still, on these grounds, we may presume that its chance of survival is about five times as good as that of _Meloë_, which lays ten thousand eggs. The larva is said generally to attach itself to a male bee, which is hatched earlier than his mate, and to pass on to the female at the nuptial period; but in any case it eventually slips on to the egg that she lays. This forms the food of the larva during the remainder of this stage of its existence. It then moults and assumes a new form, capable of feeding on the honey (Fig. 13, B); and, after further changes, becomes a pupa, and then assumes the imago condition.