Another point to ponder on is the wonderful complexity of the instincts which govern the actions of spiders; the extraordinary operations they can perform, entirely untaught, and of the object of which it is impossible to believe they are aware. We have seen that, in the most highly organised species, the sense organs—except perhaps that of touch—are but moderately developed, and the power of memory, the basis of intelligent action, but feeble; yet their inherited impulses suffice for all ordinary emergencies, and recur with unfailing precision at the proper periods of their lives. They are machine-like, perhaps, but what extraordinarily competent machines! The light of what we call intelligence burns low, but a glimmer of it can be detected here and there. If one comes to think of it, the egg of a creature of complex instincts is a particularly wonderful atom; it contains not only the germs of all the complicated bodily structure, but there are bound up in it also the impulses that are to come into play at certain definite periods only of the spider’s life-history. And these impulses are not mere vague reminders that now is the time to spin a snare, or to weave an egg-cocoon; they prescribe precisely how it is to be done, involving perhaps a dozen different spinning operations in one unvarying order. Viewed in this light, the germ of an insect or a spider would seem in a sense to be more complex than that of an animal whose vague instinctive impulses are under the direction of intelligence, and can be carried out in a variety of ways according to circumstances. One of the most surprising things about the egg of a spider is the amount of _energy_ stored up in it. A bird’s egg, huge in comparison, contains material sufficient to build up the body of a fledgeling just sufficiently active to be able to accept from the mother that first nutriment without which it will speedily die. But turn back to the account of the tarantula-spider. Its egg is small—perhaps the twelfth of an inch in diameter; yet it not only produces a spiderling complete in form, and provided with all the complex instincts of its tribe, but there is so much energy to spare that, for months, without any new food-supply, the young spider can lead an active life, frequently descending from and remounting its mother’s back, and can even put forth silk on its own account! The objects which a conjuror produces from a hat seem trifles in comparison with the outcome of a spider’s egg—the actual material seems astonishing from so small a source, but whence comes all this surprising surplus of energy? Fabre suggests that it is supplied by the direct rays of the sun, to which the Tarantula exposes in turn all parts of the egg-cocoon.