"A continued supply of fresh food must be given to those insects which are feeding, and a bit of moist sponge thrust into the mouth of the bottle will prevent drowning, and furnish moisture to such as need it. By means of a broad paste brush and spoon the frass may be daily removed from the earth, which should be kept in a fit and moist condition--neither too wet nor too dry. In the winter, when insect life is dormant, the earth may be covered with a layer of clean moss, and the cages put away in the cellar, where they will need only occasional inspection, but where the moss must nevertheless be kept damp. Cages made after the same plan, but with the sides of wire gauze instead of glass, may be used for insects which do not well bear confinement indoors, the cages to be placed on a platform on the north side of a house, where they will receive only the early morning and late evening sun." _Detailed Instructions for Rearing._--In the rearing of insects every worker will develop a number of methods of value, and it is only by careful study and comparison of the experiences of all that the best system can be elaborated. For this reason I have, in what follows, quoted, in a more or less fragmentary way, the experiences of different entomologists. As is remarked by Miss Murtfeldt, in an interesting paper read before the Entomological Club of the American Association for the Advancement of Science, August 20, 1890, "there is a great individuality, or rather specificality, in insects, and not infrequently specimens of larvae are found for which the collector taxes his ingenuity in vain to provide. Not the freshest leaves, the cleanest swept earth, or the most well-aired cages will seem to promote their development." The greatest care and watchfulness, therefore, are necessary to insure success in the rearing of larvae. In many cases such larvae can only be successfully reared by inclosing them in netting on their food-plant out of doors. It is a frequent device of Lepidopterists also to inclose a rare female in netting placed on the food plant of the species, where the male may be attracted and may be caught and placed in the bag with the female, when copulation usually takes place successfully, or a male may be caught in the field and inclosed with such female. Mr. W. H. Edwards, where the plant is a small one, uses for this purpose a headless keg covered at one end with gauze, which he places over the plant inclosing the female.