[Illustration: _The Nest of the Gipsy-moth._]
[Illustration: _Eggs of Lackey-moth._ (_Natural size, and magnified._)]
Let us now pass on, to mention, that many eggs are deposited without any special protection of the kind we have described, and without what would be with propriety termed a nest. A moth, called the lackey-moth, frequently ornaments the young twigs of trees in our gardens with exquisite bracelets of glistening white eggs, looking like beads. From two to three hundred of these eggs are glued on by the insect around the twig, by means of a tenacious waterproof cement, and are arranged with an accuracy of the most marvellous character, in a close spiral line upon the twig. The cement employed by the insect in uniting her eggs, and in varnishing them over, is so hard as to serve the purpose of a covering, which admirably casts off the rain, and preserves the eggs free from injury by the elements all the winter long. Many eggs are simply glued on irregularly upon the stems and leaves of plants, their shells or outer coating, together with the protecting varnish, being sufficient to preserve them from the inclemencies of the weather; but some are piled together with the most striking regularity, in regular columns of eggs.
In addition to these, it is proper to state, that some insects lay their eggs in the body of the young of others. Of these, those which are most dreaded by the insect tribe are the little but terrible flies, called Ichneumons. They are so called because in their actions they agree with the popular account of those of the ichneumons of Egypt, which were venerated as the destroyers of the eggs of serpents and crocodiles. "Such," say Messrs. Kirby and Spence, "is the activity and address of the ichneumons, that scarcely any concealment, except perhaps the waters, can secure their prey from them; and neither bulk, courage, nor ferocity, avail to terrify them from effecting their purpose. They attack the ruthless spider in his toils; they discover the retreat of the little bee, that for safety bores deep into timber; and though its enemy, the ichneumon, cannot enter its cell, by means of her long ovipositor (organ for depositing the egg), she reaches the helpless grub, which its parent vainly thought secured from every foe, and deposits in it an egg, which produces a larva that destroys it. In vain does the destructive _cecidomia_ of the wheat conceal its larvæ within the glumes that so closely cover the grain; three species of these minute benefactors of our race, sent in mercy by Heaven, know how to introduce their eggs into them, thus preventing the mischief they would otherwise occasion, and saving mankind from the horrors of famine. In vain, also, the _cynips_, by its magic touch, produces the curious excrescences on various trees and plants, called gulls, for the nutriment and defence of its progeny. This parasite insect discovers its secret chamber, pierces its wall, however thick, and commits the destroying egg to its offspring." In vain, also, might we add, does the sand-wasp excavate her deep cell for her young ones; for when once the ichneumon has discovered the retreat, the destruction of the young larvæ is inevitable. She pierces through the defences piled over the mouth of the cavity, with all the precision and patience of a higher creature, and rests not until she has thrust down her long ovipositor, and placed the egg in the body of the helpless prisoner below, when she flies away, confident that the days of her victim are numbered, and having thus doomed him to be eaten up alive! The common caterpillar, which, by its ravages in our cabbage rows, makes itself a little too familiar to us, has a fierce enemy in these flies; they dart upon it, pierce its body in many places, laying an egg in each wound; these in due time become hatched, and eat their way out of the body of the poor caterpillar, who soon dies, while the larvæ, after undergoing their proper transformations, become perfect insects themselves, fully equipped to proceed to the same work in some other individual of the caterpillar kind.