Plenty of ventilation, without allowing actual wind to penetrate, should be provided, and only the best colza oil be used. If made to order, a great advantage will be found in having the right-hand side to open outwards (from the back) instead of opening on the front, as the lantern can then be more easily trimmed when strapped on the body without the necessity of its removal for that purpose.
The chip boxes, which some entomologists use instead of the cyanide bottle to take the moths off the trees, are simply the various sized ointment boxes of the druggist, strengthened by papering, or by pieces of glued linen crossing them. Many use them, chiefly those of the old school, in preference to anything else — De gustibus, etc..
The objections to a general use of these boxes are many. First, you must provide yourself with a large bagful or pocketful of these boxes on starting out, as one moth only goes in each box, leaving one pocket empty on the reverse side of your coat to receive the boxes when filled, in order not to mix the empty with the full ones. Second, you are not quite sure at night as to "rubbed" or "chipped" specimens, and may find in the morning your boxes filled with worthless things, which a brief introduction to the cyanide bottle would long before have revealed.
Third, the most important fact, that though there are many insects which rest quietly when boxed, there is a large percentage which pass the time of their captivity in madly dashing themselves against the walls of their prison, and a boxed insect of this turn of mind presents a sorry sight in the morning, many stages, in fact, on the wrong side of "shabby-genteel." Then when, after a night's severe work, you are limping home in the morning, thinking how cold it is — until roused to action by the appearance of some unexpected insect — then, indeed, how much more cold and hollow seems the world, when, suddenly catching your tired foot in a stump or tangle of grass, you roll over on the full pocket side and hear (and feel) the boxes burst up on the unhappy moths within. I have gone through it all, and I don't like it!
ASSEMBLING - I had almost forgotten to mention another extraordinary way of catching moths (chiefly Bombyces), by what is called "assembling," which is exposing in a gauze-covered box a virgin female, who, by some mysterious power "calls" the males of the same species around her in so infatuated a manner that they will even creep into the collector's pocket in their quest of the hidden charmer.
In a highly interesting paper in the "Country," of 2nd Oct., 1873, Dr. Guard Knaggs gave a very full account of the theory and practice of "assembling," so interesting, indeed, that I venture to reproduce it in extenso. He says:
"The generally accepted theory is that each female should, at one or other period of her existence, captivate at least one of the opposite sex, though it will be found by experience that some species possess a far more potent influence for this purpose than others.
"It may be set down as a rule that females which are captured at rest during the time of day or night at which they should naturally be upon the wing are unimpregnated, and may be used for attracting with fair chances of success. There may be exceptions to this rule; my opinion inclines to the belief that the butterflies take wing before impregnation; but of this I am certain, namely, that the females of butterflies — at any rate of certain species — have considerable influence over the males. Doubtless, too, there are many skittish Geometrae or slender-bodied moths, and Pyrales, or Pearls, which are easily frightened, the females of which will rush from their places of concealment even before they are prepared to start on the mission of ovipositing. The converse of this rule, that female insects captured on the wing are almost invariably impregnated, may be taken as an axiom, at least so far as the moth tribe is concerned. Of course females which have made their appearance in our breeding cages are the most eligible for the purpose of attraction; but whenever we breed these with the intention of using them for attracting, we must bear well in mind that the rearing process, whether from the chrysalis, the caterpillar, or the egg, must be conducted under surrounding conditions of temperature, etc.., as nearly as possible resembling those to which they would be subjected in their natural state. Otherwise, if we retard their appearance by keeping our breeding-cages in too cool a situation, we shall be too late for our sport, or at best capture only worn specimens; while, if we force them by an unnatural state of warmth, the males will not have made their appearance at large by the time we are ready to arrive upon the hunting-ground. Having furnished ourselves with a bred female, the next procedure will be to construct a cage for her reception in such a manner that the males will be compelled to keep within a respectful distance, and formed of such material as will permit the air to readily permeate the sides of the prison.
Fig. 55 — Assembling cage.