[FOOTNOTES:]

[1] It is well known that ants, by touching the skin of aphides, extract therefrom a secretion of viscous matter, which nourishes them. They will frequently carry off the aphides to their habitations, and keep them there; thus one may say they keep a cow in their stable.

[2] The preservation of insects, and their preparation for collections, necessitates some precaution. Entomologists are in the habit of spreading them out on a small board, and arranging the legs and antennæ by means of large pins. The wings should be dried by placing them on strips of paper, which preserves them. These precautions are indispensable if it is wished that the insects in a collection should retain their distinctive characters. Worms and caterpillars can be raised in pots filled with earth, if carefully covered over with muslin or wire gauze with very fine meshes. The process of hatching may give rise to many interesting observations.

[3] It frequently happens that in a small aquarium, constructed after this fashion, the animals escape. This is avoided by covering the vase with a net.

[4] The infusion of parsley has the advantage of not sensibly obscuring the water.

[5] Detailed accounts in Vol. lxxxiii., pp. 243 and 292 of “La Nature.”