Essays on the Microscope / Containing a Practical Description of the Most Improved Microscopes, a General History of Insects, etc., etc.

by George Adams

THE METHOD OF COLLECTING THEM IN THEIR CHRYSALIS STATE.

Butterflies and moths may often be found in chrysalis under the projection of garden walls, pales, out-houses, in summer-houses, &c. and frequently affixed to the food on which the caterpillar fed. A great variety of moths in the pupa state may with more certainty be found, during the winter months, by digging under the trees on which they feed, particularly under the oak, willow, lime, and elm trees. When they are procured in this manner, they should be placed as soon as convenient in the breeding box before described, and kept covered with moist earth till the ensuing spring; when, as soon as the weather is mild, they may be dug up and placed somewhat nearer the surface of the mould, and in that manner left to come out of themselves. Should the collector not succeed in procuring chrysalides by this method, it will frequently happen that his labour will be amply recompensed by obtaining a variety of beetles.

THE METHOD OF COLLECTING THEM IN THEIR FLY OR PERFECT STATE.

The extreme delicacy of the wings of moths and butterflies will not admit of their being caught without injury, but in nets made of the finest materials. It will be necessary, therefore, that the collector should provide himself with a net properly adapted to this purpose: the one [here] represented has, after long experience, been found to answer extremely well. Fig. A shews the net expanded ready for use; a exhibits the part made of fine Scotch gauze, which should be previously dyed green; b b, the sticks; these should be of some light wood. To render them compact and convenient for carriage, they are made to take to pieces somewhat in the manner of fishing-rods, and connected by means of screws or hollow brass ferrils fixed to the end of each: there are three of them for each side of the net. Fig. B shews one of the sticks; a, the brass ferril; b, the end of the next stick, which fixes tight into it; to the upper end of the sticks, at c, is joined in like manner a piece of cane bent to a proper shape. Instead of three pieces of wood, as here described, the other stick may consist of one entire piece, and be used as a walking-stick. The gauze must be edged with two pieces of binding sewed together, to receive the sticks when joined; and, as the sticks are taper, so must be the cavity to receive them. At the lower part the gauze is to be turned up about six inches, so as to form a bag, Fig. A, c. At the extremity of the gauze, next the handles, two pieces of tape must be fixed on each side, d d, of sufficient length to pass through a hole bored in the stick, and then be tied in a loop, so as to prevent the gauze from sliding on the sticks. At the upper part of the net where the canes meet, e, the cavity should be closed by a few stitches, that the sticks may shut even together. The net may be about a yard in width when expanded, and the length of it a yard and an half: the size, however, may be varied at pleasure. The gauze should be deprived of its glazing by being soaked for a short time in warm water; but, if dyed green, which is usually the case, this will be unnecessary. The handles are to be held one in each hand, when the net is used.[161]

[161] Though this net be principally intended for catching moths and butterflies on the wing, it maybe usefully applied to another purpose: if one person expand the net under a bush or branch intended for examination, and another shake the bush, or beat it well with a stick, numbers of caterpillars, as well as some of the minuter kinds of coleopterous, and other insects, will fall into the net. By these means moths are likewise often taken, as they remain in a torpid state during the day, sheltered in the bushes.

Besides the gauze net for catching butterflies, &c., the collector should be provided with a pair of forceps, made of steel, about nine or ten inches in length, and of the shape represented in the figure;[162] the fans are to be covered with fine green gauze. This instrument will in many instances be found exceedingly commodious, as being of more general use; it is very portable, and possesses this advantage over the net, that the insect caught in it will be more confined, and consequently not so liable to injure its down. If the insect be met with on the trunk of a tree, paling, or any flat surface, it may be readily caught; if on a leaf, both may be enclosed in the forceps. Whilst in the forceps, it should be pressed with the thumb, or, if the creature be small, with the thumb-nail, sufficient to stupify, but not crush it.

[162] This figure shews the forceps in the proportions in which they have been generally made; I would, however, recommend the fans to be considerably larger, and the handles shorter. The form of the fans has commonly been either hexagonal, or, the worst of all, triangular; experience has taught me that the shape as here given is to be preferred, as being less liable to miss the insects, who are usually upon their guard, and frequently elude the vigilance of their pursuers. A front view of the fans is given, the better to shew their form; but it is obvious that they must be placed in a contrary direction, so as to flap on, not slide over, each other.

The next articles necessary to be provided, will be two or three oval chip boxes, cut sufficiently flat for the pocket, and lined at top and bottom with thin cork; and a cushion well stored with pins of various sizes.