any advocates at all.
When your frame is completed, sew round it a strip of strong calico, to which the net itself may be afterwards sewn, for the lighter material of the net is too delicate to stand the constant friction against the metal or cane frame.
The material usually employed in making the 'bag' is called leno. It can be purchased at most of the drapers' shops, and three colours – white, yellow and green – are usually kept in stock. Measure the circumference of your net frame, and see that you get sufficient leno to make a good full net. Suppose, for instance, that the circle of your frame measures thirty-six inches round, then your leno should be at least forty inches in length. Fold this double, and then cut out two pieces of the shape shown in fig. 42, letting the depth of the net be nearly or quite equal to the width of the material. There is nothing to be done now but to stitch the bag together and sew it to the calico on the ring.
Fig. 42.
At first you will find the leno rather stiff and harsh, but a damping and good rubbing between the hands will soften it down; or, if you prefer it, you may soften the material by a slight washing before cutting out the net. The latter is perhaps the better plan, for the washing will remove the objectionable 'dressing' that renders the material rather hard and stiff.
Of the three colours mentioned above, green is the one most generally chosen, because it is more in harmony with the surroundings of a butterfly catcher; but many prefer the white leno to the green, as the insects are more easily seen in a net of this colour. Yellow is certainly not a desirable tint.
As a rule it will be necessary to kill an insect as soon as it is captured. This is always the case with butterflies unless you require to keep them alive either to watch their movements or to obtain eggs. For this purpose you will require a killing bottle or box containing some volatile substance.
The selection of this necessary piece of apparatus is a point deserving of much consideration, for so many different forms are in use by different entomologists, and so many advocates each declare that his own plan is far superior to that of any of the others, that the final decision is not to be worked out in a moment. The best thing for a beginner is to try as many as he can, and then, after some considerable experience of his own, he will be able to decide which apparatus suits himself best.
I recommend this because it is impossible to say of any one plan that it is the best, for that which gives perfect satisfaction to one individual will often fail to give anything but annoyance in the hands of another.
To enable my young readers to follow the advice I have just given, I will describe some of the commonly used killing arrangements and show how they should be used.
I will take first the 'cyanide bottle.' This is a wide-mouthed bottle, containing a very poisonous substance called cyanide of potassium. It is fitted with a good sound cork. The 'cyanide' is a solid substance, and must be fixed in some way or other at the bottom of the bottle so that it cannot shake about and damage the butterflies.
Fig. 43. – The Cyanide Bottle.
A cyanide bottle can be purchased ready for use at the cost of a shilling or thereabouts; but if you are old enough to be trusted with deadly poisons, you may buy the 'cyanide' of a chemist who knows you well and is satisfied as to your intentions, and then prepare your own. Every entomologist should know how to do this, for the poison loses its power after some time, and it is not always convenient to leave your bottle in the hands of a chemist or a 'naturalist' to have it recharged. This will cost you more than it would to do it yourself, but that is nothing compared with the annoyance that may result when, the night before an anticipated butterfly hunt, you are calmly told that 'your bottle will be ready in a few days.' You can charge it yourself in a few minutes if you can manage to keep a small supply of 'cyanide' in stock, and it is ready for use very shortly after.
Here is the modus operandi. – Purchase an ounce or two of the cyanide of potassium, and immediately put it into a stoppered or well-corked bottle. Label it at once, not only with the name, but also with the word Poison in very large and conspicuous letters. This dangerous chemical is often sold in sticks that look much like certain 'sugar sticks' I was acquainted with in my younger days; but whether this is or is not the case with your cyanide, see that the bottle is kept quite out of the reach of the inquisitive and sugar-loving juveniles of the house.
The quantity above mentioned is more than you will require for the first 'charge,' but you will soon experience the convenience of having a supply always at hand for recharging when your cyanide bottle fails to do its work expeditiously, or when an accident calls for the somewhat sudden appearance of a new one.
Now procure a bottle for your work. Its mouth must be wide enough to take the largest insect you hope to catch, and the widest part of the bottle need not be much larger. Get a perfectly sound cork to fit it tightly; and, to insure the more perfect exclusion of air, paint over the top of the cork with melted paraffin wax.
Dissolve a few drams of the cyanide in a little water, using a glass rod to stir up the mixture till the solid has all disappeared; and be careful that neither the solid nor the solution touches the skin if it should be in the slightest degree scratched or broken. Now sprinkle plaster of Paris into the solution, a little at a time, and stir all the while. As soon as the mixture begins to set, pour it into your bottle as cleanly as you can – that is, without touching the sides – and press it down with the flat end of a stick if it is not level. Now cork it, and put the bottle away in a cool place till required for use.
This is, I think, the best way of charging the bottle; but there are two other common methods that may, perhaps, be regarded as a little more simple. One is this: put a few small lumps of the 'cyanide' into your bottle, and then cover them with a stiff mixture of plaster of Paris and water, and press down as before. The other plan is to cover the 'cyanide' with a few thicknesses of blotting paper, cut just a little larger than the inside of the bottle. The first of these two methods is fairly satisfactory, but I have always found that the charge, when made in this way, has a tendency to become wet and pasty, in which condition it will spoil the wings of the insects. The other is very objectionable, especially for field work, for the blotting paper fails to keep its place while you are on the chase. If the plaster is used, the mixing must be done quickly and without hesitation, or the mixture will become solid before you can press it into your bottle.
We will not enter now into the pros and cons of the cyanide bottle, but will consider the advantages and disadvantages of the various methods of killing the insects after we have noticed a few more.
The 'laurel box' has had many devoted advocates, although it does not seem to be much in use now. It is a very good arrangement, however, but is a little more troublesome than the cyanide bottle, as it requires frequent replenishing.
A very good laurel box may be prepared as follows. Get a small tin box of cylindrical form, measuring about five inches by two, and cut a circle of perforated zinc or wood just the size to fit it snugly as a false bottom without any danger of falling out of its place. Now gather some of the young leaves of the green laurel bush, and beat them almost to a pulp with a mallet or hammer. Place this in your tin box, and press down the perforated false bottom on it. The bruised laurel leaves give off a very powerful odour, which stupefies butterflies immediately.
Fig. 44. – Section of the Laurel Box.
a, space for insects; b, perforated partition; c, bruised laurel leaves.
Of course the reader may be able to think of various other ways in which the laurel box may be made. Any arrangement will
