_Instinct of Insects_.--One of the regular course of free scientific lectures delivered at the Paris Sorbonne this last winter, under the auspices of the Minister of Public Instruction, was by the distinguished naturalist M. Milne-Edwards, on the instinct and intelligence of animals. Taking for his text the saying of Linnaeus, _Natura maxime miranda in minimis,_ he spoke principally of the instinct of insects, and especially of solitary bees. These hymenoptera, in fact, afford one of the most striking examples known of that faculty which impels an animal, either for its own preservation or for the preservation and development of its offspring, to perform the most complicated and intelligent actions, readily and skilfully, yet without having learned how to do them. One species, the carpenter-bee (_xylocopa_), bores in the trunks of trees galleries running first horizontally and then vertically to a considerable depth. She then collects a quantity of wax and honey. The honey she kneads into a little ball of alimentary matter, in the midst of which she deposits her first egg. With the wax she constructs a horizontal partition, formed of concentric annular layers; this encloses the cell. On this partition she deposits a second egg, enclosed like the first in the provision destined for the support of the future larva; and over it builds another partition of wax; and so on, to the top of the vertical cavity. Then she dies; she never sees her offspring. The latter, so long as they remain larvae, feed upon the honey which the maternal foresight provided for them; and so soon as they have passed through their second metamorphosis and become winged insects, issue forth from their retreat, to perform in their turn a similar labor. Another species of solitary bee, whose larva is carnivorous, resorts to a still more wonderful, but, it must be confessed, very cruel, expedient to supply the worm-like progeny with food. She constructs a gallery or tunnel in the earth, and crowns it with a chimney curved somewhat like a crosier, so as to keep out the rain. Then she goes a-hunting, and brings back to her den a number of caterpillars. If she kills them at once, they will spoil before her eggs are hatched; if she lets them alone, they will run away. What shall she do? She pierces the caterpillars with her venomous little dart, and injects into them a drop of poison, which Mr. Claude Bernard no doubt will analyze some day. It does not kill, it only paralyzes them; and there they lie, torpid and immovable, till the larvae come into the world and feast off the sweet and succulent flesh at their leisure.