Fig. 45.—The Chloroform Bottle.
Some entomologists recommend the solid carbonate of ammonium instead of liquid ammonia, but this is not so powerful. It must be remembered that we have the butterflies to consider, as well as our own convenience, in the selection of the poisons we use. It is the opinion of many well-known entomologists that 'insects cannot feel pain,' and that we are therefore at liberty to deal with them in any way we please. Still it is as well to save all possible suffering, and be satisfied with no killing box that is not practically instantaneous in its effects.
Among other poisons used by entomologists I may mention sulphur fumes and tobacco smoke. The former may be obtained by burning a little sulphur or a sulphured lucifer match under the perforations of a killing box of the pattern described, and the latter—well, every smoker knows that. I should at once condemn the former method, at least for field work, as troublesome and inconvenient; and as to the other, I have tried the effect of a puff (and many puffs) of tobacco smoke on an imprisoned insect, but was so dissatisfied with the result that I am not likely to do so again.
We have now considered a good many insecticides more or less suitable to our purpose, but there still remains the unsolved problem as to which is the best. Each one has its advantages. For convenience nothing beats the cyanide bottle. It is very speedy in its action, and the use of a bottle is a little preferable to a metal box, for you can always satisfy yourself as to its efficiency without
opening it. Cyanide, chloroform, benzole, and some others render the insects more or less brittle and stiff, so that it is not so easy to 'set' them for the cabinet. Perhaps, if you happen to have a supply of growing laurel close at hand, you cannot do better than stick to the laurel box. The time taken in bruising up a few leaves is inconsiderable, and the moisture given off from them will keep your insects moist and supple, or will even 'relax' them if they have become rigid. But try various plans for yourself, and you will be able to settle a question which all the entomologists in the world cannot answer for you—which method answers best in your hands.
The next item for our consideration is the 'collecting box.' This is merely a box in which the butterflies are pinned as soon as they are dead. Here, again, we shall note a few variations from which a selection can be made according to the means or the ingenuity of the reader. For a couple of shillings you can obtain a good zinc collecting box, lined with cork, of oval form (a most convenient shape for the pocket), and quite large enough for one day's captures; and half that modest sum will purchase a wooden box, also lined with cork, adapted to the same purpose.
As with many other things, so with collecting boxes, the cheapest is often the dearest in the end. You may feel inclined to save a shilling by buying a wooden box, but you are sure to discard it after a little practical experience for a metal one. We shall speak a little later on concerning the advisability of 'setting' the butterflies as soon as possible after capture; but this is not always practicable, especially after a good day's catch. Now, if the insects are pinned in a wooden box, they soon become dry and rigid, and consequently cannot be 'set' till they have been put through the more or less tedious process of 'relaxing.' If you use a wooden collecting box you will often find, on a hot and dry day, that all or nearly all your butterflies are rigid before you arrive home; but a metal box will keep them moist and supple, so that you can even put off the setting till the following day if you are unable to do it immediately after your return.
Another point worth considering is the best economy of space. If your collecting box is only about one inch deep inside, you have room for only one layer of pinned insects; but a box only a little deeper may be lined with cork both at top and bottom, and thus be made to accommodate double the number. The zinc boxes sold by the dealers are generally lined with cork in this manner, and are,
of course, deep enough for the double layer of specimens; but the wooden boxes are sometimes lined on the bottom only. After these few remarks you will at once see the economy of expending the extra shilling on the former.
Although the prices of collecting boxes are low, yet there are many who would prefer making their own, and there is much to be said in favour of this. A great deal of pleasure is to be derived from the construction of your own apparatus, especially when that apparatus is afterwards to be used in the pursuit of a delightful hobby. During the whole of the time thus engaged, you are looking forward with the most pleasurable feelings to the glorious treat before you, and every joint you make seems to bring you nearer to the realisation of your joys. During the bleak winter months there is no better employment for an entomologist who has a little spare time than the preparation for the next outing. It is just one of those artful schemes by which he seeks to get as much pleasure out of life as it is capable of affording. How many there are who, for the lack of a pleasant and instructive hobby, find their leisure hours the most dismal of all, and who complain of the toil and wearisomeness of their lot! The mournful thought with them is, 'Is life worth living?' but who ever heard such an expression from the lips of an active entomologist?