In general entomologists content themselves with collecting insects without studying the manners and mode of life of these animals; yet they thus fulfill but a part of their duty, for it is necessary for the progress of science to have exact notions on this subject. Thus, it is well to indicate, whenever it is possible, not only the locality where the insect is found, but, besides, the nature of the locality, the names of the plants on which the variety is found, and all the particulars relative to its manner of life. It would be interesting to have samples of the products of the industry of these little beings, the nest of bees and ants, the combs of wild bees, cocoons, etc. The stuffs supplied by insects and used in the arts, are equally important to collect and study with regard to their mode of production. Besides, we shall call the attention of travellers to the alteration made by insects in the plants they inhabit, the manner many of them pierce the bark of trees or even the wood, eat or roll the leaves, or cause in them, by their stings escrescences, etc. Specimens of these alterations would be of great interest to enthomology, especially when united with the insect that occasions them. We urge travellers, likewise, to look for cheniles and the other larvae, and to preserve some of them alive, in order to obtain a perfect insect, or, at least, a crysalis. Larvae whose origin is unknown would be of scarce any interest to the museum, while a collection in which each larvae is united whith the perfect insect would be of great interest. Besides the insects that live as parasites on other animals should not be neglected. Insects are easily caught and need few instruments. The best way to take a great number of these animals at a time is to throw quickly on the plants of the meadows and lawns a cloth sack whose mouth is attached to a circle of iron, fixed at the end of a stick. By directing this instrument alternatively right and left, even the fleetest insect cannot get out, and all those that are caught by its movement, are driven to the bottom of the sack; they should be taken out one by one, either with the hand or pincers, and pierced immediately with a pin proportioned to the size of the animal. The coleopters should be pierced on the right wing (clytze), the hymenopters, dipters and lepidopters in the middle of the waist, the orthopters and nevropters a little behind, between the base of the wings.