=Breeding Cages.= These must be made of oak, or other hard wood, as pine
is apt to kill the caterpillars from its strong smell of turpentine. The
best form for these is represented in Fig. 32. The sides and front are
covered with gauze; a is a small square box, for the reception of a
phial of water, for placing the stalks of plants in, on which it is
intended the caterpillars are to feed. The most convenient size for a
breeding cage is eight inches in breadth, four deep, and one foot in
height. It is not proper to place within a cage more than one species of
caterpillar, as many of them prey upon each other. Indeed, animals of
the same species will devour each other if left without food. The
caterpillars of insects, for the most part, will only eat one particular
kind of food, so that it is better to have no more than one sort in a
cage.
There must be at the bottom of the cage earth to the depth of two
inches; this should be mixed with some fine sand and vegetable earth, if
possible, to prevent it from drying. The cages should be kept in a cool
cellar or damp place, because many insects change into the pupa
condition under the earth; so that it would require to be somewhat
moist, to prevent the destruction of the animal. The shell or case of
the pupa also becomes hard, if the earth is not kept moist; and, in that
event, the animal will not have sufficient strength to break its case at
the time it ought to emerge from its confinement, and must consequently
die, which but too frequently happens from mismanagement.
Some seasons are more favorable than others for the production of
caterpillars, and to keep each kind by themselves would require an
immense number of cages, as well as occupy much time in changing the
food, and paying due attention to them. To obviate this, some persons
have large breeding cages, with a variety of food in them, which must be
cleaned out every two days, and fresh leaves given to the caterpillars;
as, on due attention to feeding, the beauty and vigor of the coming
insects will much depend.
The larvæ of insects, which feed beneath the surface of the earth, may
be bred in the following manner: Let any box that is about three or four
feet square, and two or three feet deep, be lined internally with tin,
and a number of very minute holes be bored through the sides and bottom.
Put into this box a quantity of earth, replete with such vegetables as
the caterpillars subsist on, and sink it into a bed of earth, so that
the surface may be exposed to the different changes of the weather. The
lid should be covered with brass or iron network, to prevent their
escape, and for the free admission of air.
The young entomologist should obtain a cabinet of about thirty drawers,
arranged in two tiers, and covered in with folding doors. There is a
great convenience in this size, as the cabinet is rendered more
portable, and at the same time admits of having another of the same
size, being placed above the top of it, as the collection increases,
without injuring the uniformity, and thus the drawers may be augmented
to any extent. It is immaterial whether the cabinet is made of mahogany
or oak; sometimes they are constructed of cedar, but seldom of pine, or
any other soft wood. Small cells must be made in the inside of the
fronts for camphor.
=Corking of Drawers.= The simplest way to get the cork is to purchase it
of a cork-cutter, ready prepared, but it will be much cheaper for the
entomologist to prepare it himself. In this case, it should be cut into
strips of about three inches wide, with a cork-cutter’s knife, to smooth
the surface and to divide it. The strips should be fixed in a vice, and
cut to the thickness required with a fine saw; but grease must not be
used in the operation, as it will not only prevent the cork from
adhering to the bottom of the drawer, but will also grease the paper
which should be pasted on its surface. The black surface of the cork
should be rasped down to a smooth surface. After having reduced the
slips to about three quarters of an inch in thickness, the darkest, or
worst side of the slip should be glued down to a sheet of brown, or
cartridge paper; this should be laid on a deal board, about three feet
in length, and the width required for a drawer or box; a few fine nails,
or brads, must be driven through each piece of cork to keep it firm and
in its place until the glue is dried; by this means, sheets of cork may
be formed the size of the drawer. All the irregularities are filed or
rasped down quite to a level surface, and then polished smooth with
pumice-stone. The sheet, thus formed and finished, is glued into the
drawers. To prevent its warping, some weights must be equally
distributed over the cork, that it may adhere firmly to the bottom of
the drawer. When quite dry, the weights are removed, and the cork
covered with fine white paper, but not very thick. The paper is allowed
to be quite damp with the paste before it is placed on the cork, and
when dry it will become perfectly tight.
Insect cabinets should be kept in a very dry situation, otherwise the
antennæ, legs, etc., will become quite mouldy. The same evil will ensue
if the insect is not perfectly dry before it is placed in the
cabinet.—Should an insect be covered with mold it can be washed off with
a camel’s hair pencil, dipped in camphorated spirits of wine; in which
case, the insect must be dried in a warm airy situation, before being
placed in the cabinet.
There should always be plenty of camphor kept in the drawers, otherwise
there is great danger to be apprehended from mites; where these exist,
they are easily discovered by the dust which is under the insects by
which they are infested. In which case, they must be immediately taken
out, and rubbed clean with a fine camel’s hair pencil, and well imbued
with the solution of corrosive sublimate, and then placed near a fire,
taking care, however, that too great a heat is not applied, as it will
utterly destroy the specimen. The butterfly, sphinx and moth tribes are
extremely liable to the attack of mites, and should, therefore, be
frequently examined.