The preservation of insects that have been pierced requires some care; to prevent the lepidopters from injuring their wings in struggling, it is well, directly they are caught, to press the throat down; but, generally, it is necessary, on returning from the chase to kill quickly all the insects that have been caught, and, to attain this end, the best way is to place them dry in a tumbler surrounded with boiling water, for a high temperature kills them in a few minutes. The boxes designed for the reception of entomologic specimens should be of light wood, and, at least, two inches and a half deep; the bottom should be lined with cork or some other very soft vegetable substance and the pins should be pressed in as much as possible. When the insects are large, it is necessary, besides, to fix them by means of several pins placed around; for if one of them gets loose, he not only injures humself, but likewise damages all those whom he jostles. As soon as a box is full, and the insects dry enough, it should be shut and pasted with bands of paper on all the joints; but in warm countries, where destructive insects abound, this precaution is not sufficient; the boxes should, besides, be placed in a tin chest soldered on all sides. _Arachnides._--Animal of this class are less numerous than insects, but they merit the attention of travellers; certain kinds live in the water, but the greatest part are land animals, and live in shrubs or in holes, either in old walls, or in the ground. The industry that many spiders display in the construction of their dwelling or the snares designed to catch their prey, is very remarkable: the nests of the mygales, for example, is very curious. It would be interesting to have a collection of threads spun by exotic spiders, and the preservation of these delicate tissues is easy enough, if they are spread out on a leaf of paper dipped in gum-water. It is perhaps superfluous to add that those specimens would have little value, unless each one is accompanied by the spider that belongs to it. In fine, we will point out to travellers the kinds reputed venemous, and those which live as parasites on other animals. The preservation of the arachnides offer some difficulties; in drying, those animals lose their shape, and in alcohol, their colors; so it is necessary, as much as possible, to preserve specimens of the same kind by both these processes, and to take care to number them so that they may be easily identified.