“Notice what happens on a calm summer evening. Lured abroad by the balmy atmosphere of the twilight hours, a host of insects leave their lurking-places and come forth, guests at life’s garden party, to sport together in the air, hunt for food, and mate with one another. It is the hour when the sphinx-moths fly abruptly from flower to flower and thrust their long probosces into the depths of the corollas, where honey is stored; the hour when the mosquito, thirsting for human blood, sounds its war-cry in our ears and selects our tenderest spot to stab with its poisoned lancet; the hour when the June-bug leaves the shelter of the leaf, spreads its buzzing wings, and goes humming through the air in quest of its fellows. The gnats dance in joyous swarms which the slightest breath of wind disperses like a column of smoke; butterflies and moths, in wedding-garments, their wings powdered with silvery dust and their antennæ spread out like plumes, join in the frolic or seek places in which to deposit their eggs; the wood-borer comes forth from its hidden retreat under the bark of the elm; the weevil breaks its cell hollowed out in a grain of wheat; the plume-moths rise in clouds from the granaries and fly toward the fields of ripe cereals; other moths explore here the grape-vines, there the pear-trees, apple-trees, cherry-trees, busily seeking food and shelter for their evil progeny. “But in the midst of these festive assemblies suddenly there comes a killjoy. It is the bat, which flies hither and thither, up and down, appearing and disappearing, darting its head out this side and that, and each time snapping up an insect on the wing, crushing and swallowing it immediately. The hunting is good; gnats, beetles, and moths abound; and every now and then a little cry of joy announces the capture of a plump June-bug. As long as the fading twilight permits, the eager hunter thus pursues its work of extermination. Satisfied at last, the bat flies back to its somber and quiet retreat. The next evening and all through the summer the hunt is resumed, always with the same ardor, always at the expense of insects only. “To give you an idea of the multitude of harmful insects, especially of moths, from which the bat delivers us, I will quote a passage from the celebrated French naturalist Buffon, the most graphic historian of the animal kingdom. But first I must tell you that bats are in the habit of making their homes in old towers, grottoes, and abandoned quarries. There, in great numbers, they pass the daylight hours, hanging motionless from the roof, and thence they sally forth at the approach of darkness. The floor of these retreats becomes covered at last with a deep layer of droppings, from which we can learn the kind of food eaten by bats and judge of the importance of their hunting. Now here is what Buffon has to say of a grotto frequented by these creatures: