its fish, when caught. In order to surprise their prey while asleep in the night, owls fly out provided with enormous pupils which enable them to see in the dark, and with very soft feathers to make their flight noiseless and thus permit them to fall unawares upon their sleeping prey without awakening it by their movements. _Silurus_, _gymnotus_ and _torpedo_ bring a complete electric apparatus into the world with them, in order to stun their prey before they can reach it; and also as a defence against _their own_ pursuers. For wherever anything living breathed, there immediately came another to devour it,[232] and every animal is in a way designed and calculated throughout, down to the minutest detail, for the purpose of destroying some other animal. Ichneumons, for instance, among insects, lay their eggs in the bodies of certain caterpillars and similar _larvæ_, in which they bore holes with their stings, in order to ensure nourishment for their future brood. Now those kinds which feed on _larvæ_ that crawl about freely, have short stings not more than about one-third of an inch long, whereas _pimpla manifestator_, which feeds upon _chelostoma maxillosa_, whose _larvæ_ lie hidden in old trees at great depth and are not accessible to it, has a sting two inches long; and the sting of the _ichneumon strobillæ_ which lays its eggs in _larvæ_ dwelling in fir-cones, is nearly as long. With these stings they penetrate to the _larva_ in which they bore a hole and deposit one egg, whose product subsequently devours this _larva_.[233] Just as clearly does the will to escape their enemies manifest itself in the defensive equipment of animals that are the objects of pursuit. Hedgehogs and porcupines raise up a forest of spears; armadillos, scaly ant-eaters and tortoises appear cased from head to foot in armour which is inaccessible to tooth, beak or claw; and so it is, on a smaller scale, with the whole class of _crustacea_. Others again seek protection by deceiving their pursuers rather than by resisting them physically: thus the sepia has provided itself with materials for surrounding itself with a dark cloud on the approach of danger. The sloth is deceptively like its moss-clad bough, and the frog its leaf; and many insects resemble their dwelling-places. The negro's louse is black;[234] so, to be sure, is our flea also; but the latter, in providing itself with an extremely powerful apparatus for making irregular jumps to a considerable distance, trusted to these for protection.--We can however make the anticipation in all these arrangements more intelligible to ourselves by the same anticipation which shows itself in the mechanical instincts of animals. Neither the young spider nor the ant-lion know the prey for which they lay traps, when they do it for the first time. And it is the same when they are on the defensive. According to Latreille, the insect _bombex_ kills the _parnope_ with its sting, although it neither