A large number of the collected larvæ will have been 'stung,' much to the disgust and disappointment of the rearer; and hence the advantage of rearing your specimens from ova wherever possible, providing you keep them so well under cover that the ichneumons cannot visit your broods.
The Management of Pupæ
The disappointments connected with the rearing of Lepidoptera are by no means at an end when all have passed successfully into the pupal condition, and the number of perfect insects obtained will often fall far short of the number of pupæ in your boxes; but
we must now see what can be done to minimise the death rate of the captives.
One or more suitable boxes must be prepared for the reception of the pupæ, and the following suggestion will answer all purposes:
Get a wooden box, quite rough and unplaned inside, large enough to accommodate your pupæ with ease, and not less than eight inches deep. Make several holes in the bottom, or else knock the bottom completely out, and nail in its place a sheet of perforated zinc. Also make a lid consisting of gauze attached to a light wood frame.
Place a layer of clean gravel, about an inch deep, in the bottom, and over this a few inches of sifted soil or cocoa-nut fibre.
Now take all the pupæ that are 'earthed' in your cages, and arrange them on the prepared bed; also add to them the pupæ you may have dug out during your various excursions. Cover all with a layer of the material selected for the bed, and then add a layer of moss.
Next come the pupæ that are suspended by silky fibres, or are inclosed in cocoons. These should be fixed with pins around the sides of the box, running the pins either through the tuft of silk at the 'tail,' or the outer layer of the cocoon, or through the portion of the dried food plant to which they are attached.
Here your pupæ will remain till they emerge, and the box may be kept in any airy place where it is not likely to be forgotten, for it is essential that the perfect insects should be removed as soon as possible after quitting their cases. It does not matter much whether the pupæ be kept in or out of doors, providing they are sheltered from rain and very severe frosts; but of course, if the former, the imagines will emerge a little earlier, even if the room in which your specimens are stored has no fire.