The Butterflies of the British Isles
Part I., in the "Cambridge Natural History," where also will be found
much interesting and instructive matter connected with the caterpillar and chrysalis, to which stages only brief reference can here be made.
The Caterpillar.
The second stage is that of the caterpillar, and in some species, such as the Red Admiral, this is of very short duration, a few weeks only, whilst in others, as for example the Small Blue, it usually lasts for many months. There is considerable diversity both in the shape and, where it is present, in the hairy or spiny clothing (_armature_) of caterpillars. All, however, are alike in one respect, that is the body is divided into thirteen more or less well-defined rings (_segments_), which together with the head make up fourteen divisions. In referring to these body-rings, the first three nearest the head, each of which is furnished with a pair of true legs (_thoracic legs_), are called the thoracic segments, as they correspond to the thorax of the perfect butterfly. The remaining ten rings are the abdominal segments; the last two are not always easily separable one from the other, and so for all practical purposes they may be considered only nine in number. These nine rings, then, correspond to the abdomen of the future butterfly. The third to sixth of this series have each a pair of false legs (_prolegs_), and there is also a pair on the last ring; the latter are the anal claspers.
The warts (_tubercles_) are the bases of hairs and spines, and are to be seen in most butterfly caterpillars, but they generally require a lens to bring them clearly into view. These warts are usually arranged in two rows on the back (_dorsal series_) and three rows on each side (_lateral series_).
All the various parts referred to, or to be presently mentioned, may be seen in Fig. 1, which also shows a peculiarity that is found in very young caterpillars of the Orange-tip, and in some others of the "Whites" (_Pieridæ_). The odd thing about this baby caterpillar is that the fine hair arising from each wart is forked at the tip (Fig. 1, _a_), and holds thereon a minute globule of fluid. When the caterpillars become about half grown these special hairs are lost in a general clothing of fine hair. Fig. 1, _b_, represents a magnified single ring of the caterpillar, and this shows a spiracle and the folds of the skin (_subsegments_). The manner in which such folding occurs is to be observed in the higher study of larval morphology.
On each ring, except the second (including now the three thoracic with the nine abdominal; and so making twelve rings), the third, and the last, there is an oval or roundish mark which indicates the position of the breathing hole (_spiracle_). Through these minute openings air enters to the breathing tubes (_tracheæ_), which are spread throughout the interior of the caterpillar in a seemingly complicated kind of network of main branches and finer twigs; air is thus conveyed to every part of the body. In the event of one or two air-holes becoming in any way obstructed, the caterpillar would possibly be none the worse; but if all the openings were closed up effectually, it would almost certainly die. Total immersion in water, even for some hours, is not always fatal.
Turning again to the "feet" of the caterpillar, it will be seen from the figure that the true legs (_a_) differ from the false legs (_b_) in structure. The former are horny, jointed, and have terminal claws; the latter are fleshy, with sliding joints, and the foot is furnished with a series of minute hooks which enable the caterpillar to obtain a secure hold when feeding, etc. The false legs are also the chief means of locomotion, as the true legs are of little service for this purpose. The true legs, however, appear to be of use when the caterpillar is feeding, as the leaf is held between them so as to keep it steady whilst the jaws are doing their work.
In the accompanying figure of the head of a caterpillar the mouth parts are clearly shown. The biting jaws (_mandibles_) are slightly apart, above them is seen the upper lip (_labrum_), and below them is the under lip (_labium_ or _lingua_). The _maxillæ_ are very tiny affairs, but they should be noted because in the butterfly they become the basal portions of the two tubes which, when united together, form the sucking organs (_proboscis_). The eyes, or ocelli as they are termed, are minute, and are said to be of slight use to the caterpillar as organs of sight, so that it probably has to depend on its little feelers (_antennæ_) for guidance to the right plants for its nourishment. Attention should also be given to the spinneret, as it is by means of this that the silken threads, etc., for its various requirements are provided; the substance itself being secreted in glands placed in the body of the caterpillar. The palpi are organs of touch, and seem to be of use to the caterpillar when moving about.
Immediately after hatching, many caterpillars eat the egg-shell for their first meal; they then settle down to the business of feeding and growing. It should be remembered that it is entirely on growth made whilst in the caterpillar stage that the size of a butterfly depends. In the course of a day or two the necessity arises for fasting, as moulting, an important event, is about to take place. Having spun a slender carpet of silk on a leaf or twig, the caterpillar secures itself thereto, and then awaits the moment when all is ready for the transformation to commence. After a series of twistings from side to side and other contortions, the skin yields along the back near the head, the head is drawn away from its old covering and thrust through the slit in the back, the old skin then peels downwards whilst the caterpillar draws itself upwards until it is free. The new skin, together with any hairs or spines with which it may be clothed, is at first very soft. In the course of a short time all is perfected, and the caterpillar is ready to enter upon its second stage of growth. At the end of the second stage the skin-changing operation is again performed, and the whole business is repeated two or more times afterwards. Finally, however, when the caterpillar has shed its skin for the last time, the chrysalis is revealed, but with the future wings seemingly free. These, together with the other organs, are soon fixed down to the body by the shell, which results from a varnish-like ooze which covers all the parts and then hardens.
Generally speaking, newly hatched caterpillars, though of different kinds, are in certain respects somewhat alike, but the special characters of each begin to appear, as a rule, after the first change of skin (_ecdysis_), and these go on developing with each successive stage (_stadium_) until the caterpillar is full grown. The form assumed in each stage is termed the _instar_, therefore a caterpillar just from the egg would be referred to as in the first instar; between the first and second changes of skin, as in the second instar, and so on to the chrysalis, which in the case of a caterpillar that moulted, or changed its skin, four times before attaining full growth, would be the sixth instar, and the butterfly would then be the seventh instar. In practice, however, it is usually the stages of the caterpillar alone that are indicated in this way.
The Chrysalis.
The term _chrysalis_ more especially applies to such of them as are spotted or splashed with metallic colour, as, for example, the chrysalids of some of the Fritillaries. The scientific term for the chrysalis is _pupa_, which in the Latin tongue means "a doll or puppet."
In passing to the chrysalis stage the caterpillars have sometimes to make rather more preparations than in previous skin-changing provisions. Those of the Swallow-tail, Whites, Orange-tip, and similar kinds have to provide a silken girdle for the waist as well as a pad for the tail. Chrysalids that hang suspended, head downwards, such as the Vanessids, Fritillaries, etc., are attached by the cremaster--a hooked arrangement on the tail (Fig. 5)--to a pad of silk; others, such as the Blues and the Coppers, appear to be held in position on a leaf, or some other object, by means of a fine girdle of silk, or sometimes a few silken threads spread net-like above and below them--rudiments of a cocoon in fact. Chrysalids of the Skippers are enclosed in a more or less complete cocoon placed within a chamber, formed of a leaf or leaves of the food-plant, drawn together by silken cables. Some of these chrysalids are furnished with hooks on the tail as well as with a girdle for suspension; but others have hooks only.
As almost all the chrysalids here considered are figured in the illustrations, it will be unnecessary to refer in detail to their great diversity in form, but a few general remarks on the structure of a chrysalis may be made.
If the upper (_dorsal_) surface of a chrysalis is examined, the thorax and the body divisions will easily be made out, while, by looking at the sides and the under (_ventral_) surface, the various organs, such as the wings, legs, antennæ, etc., will be found neatly laid along each side of the "tongue," or proboscis, which latter extends down the centre. All these are separately encased, but by reason of the shell mentioned in the remarks on the caterpillar, they appear to be welded together. When, however, the butterfly is ready to emerge, the shell of the chrysalis is split along the thorax and at the lower edge of the wing-cases, and the insect is then able to release itself from the pupal trappings. This breaking open of the chrysalis shell is termed dehiscence (_dehisco_, "to split open"), and the manner in which it is effected varies in different species. The emergence of a butterfly from the chrysalis is always an interesting operation to observe, and every one should make a point of watching the process, so that he may obtain practical knowledge of how the thing is done. A photograph of it will be found in the description of the Wall Butterfly.
The Butterfly.
Having safely cleared itself free of the chrysalis shell, the butterfly makes its way to some suitable twig, spray, or other object, from which it can hang, sometimes in an inverted position, whilst a very important function takes place. This is the distention and drying of the wings, which at first are very weak and somewhat baggy affairs, although the colour and markings appear upon them in miniature. All other parts of the butterfly seem fully formed, but the helpless condition of the wings alone prevent it as yet from floating off into the air. In a remarkably short time, after the insect has settled to the business, the fluids from the body commence to flow and circulate through the wings, and these are seen gradually expanding and filling out until they attain their proper size. Occasionally there is some obstruction to the equal distribution of the fluids, and when this occurs a greater or lesser amount of distortion, or cockle, in the wing affected is the result. When the inflation is completed the wings are kept straight out for a time; they are then motionless, but all their surfaces are well apart. The wings being now fully developed, the further flow of fluid appears to be arrested. It has been stated by some authorities that this fluid is fibrin held in solution, and that when the work of expansion has been accomplished, the watery medium evaporates, leaving the fibrin to harden, and so fasten together the upper and lower membranes of the wing and to fix the veins, or nerves, in their proper position. Mayer, a specialist on these matters, referring to the expansion of the wings, remarks that the blood [the fluid previously mentioned] forced into the freshly emerged wing would cause it to become a balloon-shaped bag if it were not for fibres that hold the upper and lower walls closely together. The fibres referred to, he states, are derived from those hypodermic cells which do not contribute to the formation of scales, but are stretched out from one wall of the wing to the other.
It may be well now to briefly consider some of the structural details of the perfect butterfly, so a beginning will be made with the head (Fig. 6). When looking at the head of a butterfly, the first thing to attract the attention is the very large size of the compound eye (_a_), which seems to take up the largest share of the whole affair. Although so bulky and so complex in the matter of divisions, or facets, as they are termed (the facets are not shown in figure), the power of sight is not really very keen. A butterfly can see things in a general way readily enough, but it seems unable to clearly distinguish one object from another. When engaged in egg-laying, the female butterfly rarely fails to place her eggs on a leaf or spray of the plant that the future caterpillar will feed upon, and it has been suggested that in making this unerring selection the insect is guided more by the sense of smell than by that of sight.
The horns (_c_) (_antennæ_), or feelers, as they are sometimes called, which adorn the head, are now considered to be organs of smell. These are composed of a number of rings or segments, which vary in the different kinds of butterfly, as also does the shape of the terminal rings forming what is known as the club. In Fig. 7, _e_ (Purple Emperor) and _f_ (Marbled White) represent the gradually thickened club; in _g_ (Brimstone) and _h_ (Dark-green Fritillary) the clubs are more or less abruptly formed. Our Skippers have well-developed clubs; these may be hooked at the tip as in _i_ (Large Skipper), or blunt at the tip as in _j_ (Chequered Skipper); at the base of the Skipper's antenna, that is at the point where it is inserted in the head, there is a tuft of rather long hairs.
Of the various mouth parts it will only be necessary to refer to the suction-tube, Fig. 6, _d_ (_proboscis_), often called the "tongue," which is perhaps the most important, at least to the butterfly itself, as this organ is, in a way, as useful to it in the perfect state as were the very differently constructed strong biting jaws (_mandibles_) of its caterpillar existence. These latter in the butterfly are only microscopically represented, and the suction-tube of the perfect insect is an extension of the maxillæ, which in the caterpillar are not conspicuous. When not engaged in probing the nectaries of flowers for the sweets they contain, the suction-tube is neatly coiled up between the palpi (Fig. 6, _b_). Its great flexibility is due to the many rings of which it is composed. Although seemingly entire, it is really made up of two tubes, each being grooved on its inner side, and forming, when the edges are brought together, an additional central canal, through which the sweets from the flowers and other liquids are drawn up into a bulb-like receptacle in the head, whence it passes into the stomach. When it is remembered that the passage of sweet, and no doubt sticky, fluid through the central tube would most probably result in its walls becoming clogged, there is reason to suppose that the method of construction permits of the canal being cleansed from time to time.
The important divisions of the body are the thorax and the abdomen. The former is made up of three segments (named the pro-, meso-, and meta-thorax), each of which, as in the caterpillar state, is furnished with a pair of legs; the second and third, which are closely united, each bear a pair of wings also. The legs, which in the butterfly are adapted for walking at a leisurely pace, are made up of four main parts; these are (a) the basal joint (_coxa_, _coxæ_), (_b_) the thigh (_femur_, _femora_), (_c_) the shank (_tibia_, _tibiæ_), and (_d_) the foot (_tarsus_, _tarsi_). The small joint uniting the coxa with the femur is the trochanter (_tr._). The foot usually has five joints, the last of which is provided with claws (_e_). The abdomen really consists of ten rings or segments according to some specialists. Examined from above, the female butterfly appears to have only seven rings and the male butterfly eight. This discrepancy arises from the fact that in the former sex two rings and in the latter one ring are withdrawn into the body, and so are tucked away out of sight. The organs of reproduction are placed in the terminal ring. The breathing arrangements are pretty much as in the caterpillar, but the external openings are not so apparent owing to the dense clothing of the body.
The beauty of a butterfly's wings is intimately connected with the form and colour of the scales with which they are covered, as with a kind of mosaic; but before the scales and their method of attachment, etc., are referred to, something should be said about the wings themselves. The various shapes of these organs of flight will be seen on turning to the plates, where will be found accurate portraits of every species that will be dealt with in the descriptive section later on.
A butterfly's wing consists of an upper and a lower membrane, with a framework of hollow tubes, acting as ribs, between the two layers. Fig. 9, A, shows a fore and a hind wing of the Swallow-tail butterfly. The point of attachment with the thorax is the base of the wing, and the edge farthest from the base is the outer margin (_termen_); the upper edge, or front margin, is the costa; and the lower edge is the inner margin (_dorsum_). The point where the upper margin meets the outer margin on the fore wing is the apex, but on the hind wing it is called the outer angle; the angle formed by the junction of outer and inner margins is the inner angle of the fore wing, but the anal angle of the hind wing. The term _tornus_ is sometimes used for this angle on either wing. Dividing the wings transversely into three portions, we have three areas, termed respectively basal, central or discal, and outer. These are terms used in descriptions of butterflies, and it will be useful to remember them.
The ribs of a butterfly's wings are by some authors described as veins, whilst others style the main ones nervures, and the branches nervules. Fig. 9, B, represents the venation, or neuration of the Black-veined White, and the numeral system of indicating the veins has been adopted, as it is the most simple. In another method of referring to the venation, and one that has been much in use, vein 12 of the fore wing would be styled the costal nervure, or vein; veins 11, 10, 9 (absent in figure), 8, and 7 would be the subcostal nervules 1, 2, 3, 4, and 5; 6 would become the upper radial, and 5 the lower radial; 2, 3, and 4 would be the median nervules 1, 2, and 3; vein 1 would be the submedian nervure, or vein. On the hind wing, vein 1_a_ would be the internal vein; 1 the submedian; 2, 3, and 4 the median nervules; 5 the lower and 6 the upper radials; 7 the subcostal, and 8 the costal nervures. Just near the base of the hind wing will be noted a short recurved vein (p.c.); this is the precostal vein, and so named because it comes before the costal. It is always absent in some species. Comparing the venation of A and B, it will be seen that in A the fore wing has 12 veins and the hind wing 8 veins, whilst in B there are only 11 veins on the fore wing, but the hind wing has one vein more than that of A. In the Black-veined White, vein 9 is absent on the fore wing, and on the hind wing there is one internal vein.
Dust-like as they appear to the naked eye, the scales from a butterfly's wing seen under the microscope are found to be exceedingly interesting structures and very varied in shape. Dr. Sharp describes them as "delicate chitinous bags." Chitin, it may be mentioned, is the horny substance of which the chrysalis shell is formed, and this was adverted to when discussing the chrysalis stage as a varnish-like ooze. As seen on the wings, the scales are flattened and the upper and under sides are then almost, or quite, brought together. They are attached in lines on the membrane or covering of the wing by short stalks which fit into sockets in the membrane. The arrangement of the scales, which has often been stated to resemble that of the slates on a roof, is shown in Fig. 10.
Colour is chiefly due to pigment contained in the scale or adhering to the interior of its upper side. Pigments, according to Mayer, are derived, by various chemical processes, from the blood while the butterfly is still in the chrysalis. Some scales have minute parallel lines (_striæ_) on their upper sides, and rays of light falling on these are turned aside or broken up, and so produce changes in the colouring of a wing, according to the angle from which it is looked at.
The males of many kinds of butterfly have special scales, which are known as androconia, or plumules. It is believed that these are scent organs. Whatever their particular use may be to the possessor, these androconia enable the entomologist to distinguish male specimens from females with great certainty. In the Fritillaries they are placed on one or more of the median nervules (veins 2, 3, and 4) of the fore wing. In the Meadow Brown and its kindred they form brands on the disc of the fore wing. In the Skippers they are placed in a fold of the costa in some species, and in other species they are clustered together, into more or less bar-like marks, about the middle of the fore wings. Some of these various shaped "plumules" are shown in the illustrations.
In the foregoing sketch of the life cycle of a butterfly, the object has been to condense as much necessary information as possible into a limited space. Many matters of importance to the student have not been touched on, but it was considered that, as these were more especially connected with a higher scientific phase of the subject than would here be found helpful, they might be omitted.
Collecting.
Naturally the first matter for consideration, when the formation of a collection of butterflies has been decided upon, is how to set about it. Well, there are two methods of effecting our purpose. The specimens may be purchased from a dealer in such things, or we may acquire an outfit comprising net, boxes, and pins, and go in search of the insects ourselves. Apart from its healthful and entertaining possibilities, the latter method has very much to recommend it. In the first place, those who are at all observant--and no true lover of Nature can be suspected of being otherwise--will become acquainted with the objects under natural conditions, and so be enabled to appreciate them more highly than could be the case if they were obtained in any other way. The chief purpose in making a collection of Natural History specimens should be study of some kind rather than mere accumulation.
[Sidenote: Nets.]
The net may be a simple cane ring one of home construction, or the more elaborate, but not necessarily more efficient, fabrication of steel-jointed ring with grenadine bag and telescopic handle. A good serviceable butterfly-net may be fitted up as follows. Procure a light flexible cane, about 3 feet or so in length. Next, a Y-shaped holder (Fig. 12) for the two ends of the cane will have to be made, and either tin or brass may be used for the purpose. The latter is the better metal, and the parts should be brazed and not soldered together. (If difficulty is experienced in the manufacture of this article, it may be obtained from any dealer in entomological requisites for a few pence.) The bag may be made of leno, tarletan, or fine mosquito netting; the latter is the most serviceable, and should be used wherever it can be obtained. The size of the bag at the top, where it has a wide band to take the cane, should not exceed the circumference of the cane ring when fitted in the two arms of the Y-piece; the depth should be just a little less than the length of one's arm, and the bottom should be rounded off so that no corners are available for the butterflies to get into and damage their wings. An opening about 3 inches in length is left in the seam of the bag just under the Y-piece, so that the cane may be removed and rolled up when the net is put out of action. The ring band should be covered with some stouter material to prevent it from fraying, thin leather is sometimes used for this purpose; the slit in the seam also requires protecting on each side, and strengthening at the lower end by a crosspiece. An ordinary walking-stick, with the ferrule end thrust into the longer tube of the Y, will serve as a handle to the complete net.
The dealers adverted to above generally stock a variety of nets ready fitted for use. Among these is a very useful pattern known as the kite or balloon net (Fig. 13). This is made in two sizes, and as the writer has used this kind of net for at least twenty years, he is able to speak well of its merits. It does not need a stick for ordinary work, and the long end of the socket should be about 9 inches in length.
The "ring" being made of four separate rods, in addition to the Y-piece, some care will have to be taken when a balloon net is unshipped. It will be found a good plan to leave the two short curved canes in the hem or band of the bag, remove the two straight arms from the Y-piece and the band, place these on top of the bag when folded, and then roll all up together. A canvas or linen pouch or pocket, opening at one end, may be made to contain the whole affair.
The umbrella-net, when in its case, looks very like the familiar "gamp." Its chief merit is that it is quickly put up for use, and its principal defect is that the stick, which crosses the mouth of the bag, frequently damages the quarry.
Another implement of the chase known as the "Ortner" net is used pretty extensively on the Continent. English entomologists who have used it speak of it most favourably. Its great advantage over other nets is found in the simple and rapid method of its adjustment for use.
In connection with nets it may be well to advise the wielder to remember that carrying a threaded needle is a useful practice. Tears and rents are apt to occur, and it is well to have the means of repair handy.
[Sidenote: Killing.]
Some collectors seem to be expert at killing butterflies by pressing the sides of the thorax together. The method is not, however, as satisfactory as one could wish, and so no more need be said about it. For the happy despatch of insects, the cyanide bottle is frequently used. All that has to be done is to clap the open bottle over the captive while still in the net, then draw the gauze or what-not over the mouth of the bottle until the bung can be inserted, and the whole affair withdrawn from the net.
Cyanide of potassium is a deadly poison, and no inexperienced person should attempt to charge a cyanide bottle himself. In fact, chemists are not permitted to supply the poison to unknown customers. Under certain conditions, however, a chemist might consent to make up a killing bottle, and the following instructions may help him in doing this. A fairly strong, clear glass bottle, holding about 4 to 6 ounces; the mouth must be pretty wide, and closed with a well-fitting bung that has been dipped in melted wax; if the bung is of fine grained cork, the wax will not be needed. At the bottom of the bottle place a thick layer of the cyanide, and over this pour plaster of Paris which has been mixed with water and converted into a cream-like paste: one-third of the depth of the bottle to be occupied by the poison and plaster, but only a thin layer of the latter should cover the former.
Dealers who supply cyanide bottles (uncharged) also have in stock a brass bottle for chloroform, which some people prefer as a killing agent because it does not change the colour of insects as cyanide is occasionally apt to do. In using this, the insect should be boxed, then a drop of the chloroform may be allowed to run from the bottle over the perforated lid or bottom of the box, and a finger put over the hole or holes for a short time.
The majority of butterflies, if transferred to pill boxes from the net, settle down quietly. In this way they may be taken to one's home and there placed, boxes and all, into the ammonia jar, a simple but very effective contrivance. To start one of these lethal chambers, procure a good sized pickle jar, one of the brown earthenware kind, holding about 2 gallons. At the bottom put in several layers of stout blotting-paper, and have ready a covering for the mouth of the jar. This covering may be of skin, waterproof-apron material, or even thick brown paper. Before turning the boxes into the jar, lift up the blotting-paper, drop in about half a teaspoonful of strong liquid ammonia (·880) and replace blotting-paper. Directly the boxes are in the jar, put on cover and tie it down securely. If brown paper is used, a piece of pasteboard should be put over it and a weight on top of that. Suffocation takes place directly the gas reaches the insect, but it often happens that one or more of the boxes exclude the gas longer than others. At the end of half an hour all may be removed, but the insects will not hurt in any way if left in all night.
The best kind of boxes for field work are those known as "glass bottomed," as in these the captives can be examined and, if not wanted, may be set free. It is always better to retain only those specimens that we know are really useful, rather than to incur the necessity of throwing away insects after we have deprived them of life.
[Sidenote: Pinning.]
If butterflies are pinned on the spot, a collecting box will be required, and the most useful and convenient is one of an oval shape. This should be made of zinc, and lined with cork that is held in place by zinc clips. The cork should be kept damp when in use, and the water used for damping should have a few drops of carbolic acid mixed with it so as to prevent the formation of mould. Insects may remain in such a box for several days without injury. This box will also be useful for relaxing specimens that have been badly set, or have been simply pinned during the busy season.
In the matter of pins, it is not altogether easy to make suggestions. There are, perhaps, only two makers in this country of entomological pins, and each of these supplies a large number of sizes. The selection of suitable pins will largely depend on the method of setting adopted. Black pins are, however, the best for butterflies, and are now used almost exclusively.
In pinning a specimen care should be taken that the pin passes in a direct line through the centre of the thorax. Insects that are properly pinned set better, and have a neat appearance when arranged in the collection. For regulating the height of specimens on the pin, a handy graduated stage has been devised by Dr. Scarancke (see Fig. 14). Each of the little rests are hollowed to receive the body of the insect, so suppose we wish a quarter of an inch of the pin to show below the body of a specimen, the pin is pushed through a perforation in the centre of the rest groove marked "3/16" until the point touches the wooden base, and we have the required length.
Beginners would, perhaps, find three sizes of pins quite sufficient for almost every purpose--say, Nos. 10, 8, and 5 of one maker; or Nos. 9, 17, and 5 of the other. In each case the first size pin would be suitable for small butterflies, the second size for all other butterflies except quite the largest, for which No. 5 would remain. English pins are sold by the ounce.
[Sidenote: Setting.]
Setting, as it is called, that is, spreading out and fixing the wings so that all their parts are displayed, arranging the horns, etc., is perhaps the most tedious work that the collector will be called upon to perform. The various methods will be referred to, and he must then decide as to which he will adopt. Each style may possibly be found to have its difficulties at first; but time and patience will overcome these, therefore he must be prepared for a good deal of troublesome practice before he quite gets "the hang of the thing," and can set out his specimens without removing a greater or lesser number of the scales.
First, as to the flat and high setting as practised by almost every lepidopterist abroad and by some in our own country. Boards of the pattern, shown in the illustration, will be required; also some tracing cloth, and a pair of entomological forceps, bead-headed pins, etc. In these boards, it will be noticed, the sides tilt outwards; this is to allow for drooping of the wings, which generally occurs after insects are removed from the "sets." In this case the wings would settle dead flat, which is considered to be the acme of perfection in this style of setting. Carlsbad or other foreign pins would be used for this kind of work. They are of a uniform length, about one inch and a half, but vary in thickness, and are usually sold by the 100 or 1000.
Manipulation of the specimen on these boards is as follows. Having carefully pinned it, leaving the greater length of pin below the insect, guide the pin carefully through the narrow opening (_a_ Fig. 15) and the cork (Fig. 16) below to a suitable depth, so that the body of the insect rests in the groove and the wings lie easily on the board. Then take two strips of tracing cloth, glazed side downwards, and pin them on at the end of each side of the setting-board (Fig. 17). The strip should be just wide enough to cover all but the basal part of the wings. Now pass the strips over the wings, press one side lightly with the fingers of the left hand while the wings are moved into position with the setting needle (a fine needle with eye end fixed into the stick of a small penholder will do for this) from the uncovered base, a pin being inserted below the fore wing while the hind wing is brought into position, but when this has been done and another pin inserted to keep it in place, as shown in the diagram, the first pin may be removed; repeat the same operation on the other side. Other pins will be required to keep the horns, etc., in place. In dealing with the next specimen the strips will have to be turned back while it is fixed into position, then proceed as before. An imaginary line following the inner margin of the fore wings and passing through the pin on the thorax is an excellent guide to uniformity in setting. The groove will prevent the pin leaning to either side, but care should be taken that it does not incline either forwards or backwards. The strip of tracing cloth may be used more than once, but the roughness of the pin holes should be removed by drawing the strip across the back of a knife.
The setting-boards most frequently used in this country have sloping sides, and are known as saddles (Fig. 18). Where tracing cloth is used, the _modus operandi_ is exactly similar to that just described, but small pins will do for pinning down the strips, as the saddles are made of cork, or cork carpet, instead of wood.
The following method of setting butterflies on the English kind of "board" or saddle is frequently adopted. Select a suitable saddle, that is one that has the groove wide enough to take the body, and rather wider than the wings when expanded. A setting bristle will then be required. This is made, as shown in Fig. 19, by fixing a fairly long and stout bristle, or a very fine needle, or a thin length of quill, in a cube of cork; the cork cube has a stoutish and sharp-pointed pin pushed through it as indicated. Having placed the first insect on the saddle with its body comfortably resting in the groove and the wings flush with the surface, the setting bristle is then brought into action. The point of the pin is rested on the saddle directly in the rear of the hind wing, and the top of the bristle touching the saddle in advance of the front wing. Tilt the pin slightly forward until the bristle presses lightly on the central area of the wings, then with the setting needle push the wings into the required position, and at the same time drive pin of bristle into the saddle. After the wings have been secured by means of braces (triangular pieces of thin card or stout paper, with a pin through the base of the triangle), proceed in the same way with the other side. Finally, fix a brace to the tip and angle of each fore wing to keep them from turning up in drying, and a pin or two may be required for the horns if these are not in a good position. Instead of using braces, a strip of transparent paper may be pinned over the wings beyond the bristle, but in this case the bristle must be pressed across the wings at a point nearer their base than in the previous method (see lower figure in Fig. 20). In lieu of a setting bristle a length of sewing cotton may be used. Tie a double knot at one end, and through this pass the point of a pin in such a way that the cotton lies flush on the saddle when in use. Insert the pin firmly in the saddle a little in advance of the fore wing, then draw the cotton downwards across the wings and hold it taut, with the fore finger of the left hand placed on it just in rear of the hind wing. Whilst so held the wings can be got into pose with the setting needle, and braces may then be applied as previously directed.
Fig. 21 shows a specimen set by a method that is in vogue in the north. Blocks of soft pine, grooved and bevelled as in the cork saddle, are easily made. Down the centre of the groove there is a saw cut for the point of the pin to enter, and nicks are cut along the bottom edge at each end. One end of a length of cotton is knotted and fixed in a nick, then a turn is taken over the wings on one side; these are placed in position and secured by other turns of the cotton. The other side is then treated in the same manner, and the end of the cotton fastened off in one of the nicks. This is a quick and, in skilled hands, a very neat method.
As specimens after being set will have to remain on the setting boards or saddles for at least a fortnight, it will be necessary to protect them not only from dust, but from possible attack by ants, cockroaches, mice, etc. This is best ensured by placing the sets into a receptacle called a setting or drying house. Dealers supply these, but the young collector may have a knowledge of carpentry and could make one for himself. The height and depth of such a construction would depend upon the number and the width of the boards or saddles that would be put therein. The width would be that of the length of the boards, which is usually 14 inches. About a quarter of an inch of cork is cut off each end of the saddles, and grooves are cut in the sides of the house for these to run in. The back and the door should have a square of fine perforated zinc inserted in them for ventilation. As an example of holding capacity it may be well to note that a house with a height of 12 inches, and a depth of 6 inches, inside measurement, would take eighteen 2-inch boards if the grooves were cut at 2 inches apart, or twenty-four boards of same width if 1-1/2 inch only were allowed between the grooves.
In taking insects off the sets, the braces or strips should be removed from the wings, and the pins from the horns, with care, as a good deal of damage can be done in the performance of this operation, simple as it seems to be. A little twist of a brace and away goes a patch of scales, a side slip of a pin and off comes a horn.
Pending the arrival of that twelve or twenty drawer cabinet, the beginner will probably be content to arrange his specimens in boxes. A handy sized box is one measuring 14 inches by 10 when closed, and it should have a cell for naphthaline.
Before putting the specimens away into boxes or drawers they should be labelled with the date of capture, the locality, the name of the captor, and any other detail of interest in connection with it. All these particulars may be written on small squares of paper and put on the pins under the specimens.
Cabinets or boxes containing insects should always stand where they are free from damp, otherwise mould may make its appearance on the specimens. Mouldy insects may be cleaned, but they never look nice afterwards; so it will be well to bear in mind that prevention is better than cure. Where drawers and boxes are not properly attended to in the matter of naphthaline, mites are apt to enter and cause injury to the specimens. If these pests should effect a lodgment, a little benzine poured on the bottom of box or drawer will quickly kill them. The benzine, if pure, will not make the least stain, and of course the drawer or box must be closed directly the benzine is put in. Do this only in the daytime.
Rearing butterflies from the egg is much practised, and is a very excellent way. One not only obtains specimens in fine condition, but gains knowledge of the early stages at the same time. The eggs of most of the Whites, the Orange-tip, the Brimstone, and some others are not difficult to obtain, but searching the food-plants for the eggs of many of the butterflies is tiresome work, and not altogether remunerative. Females may be watched when engaged in egg-laying, and having marked the spot, step in when she has left and rob the "nest." The best plan is to capture a few females and enclose them in roomy, wide-mouthed bottles, or a gauze cage, putting in with them a sprig or two of the food-plant placed in a holder containing water. The mouth of the bottle should be covered with gauze or leno, and a bit of moistened sugar put on the top outside. Either bottle or cage must be stood in the sunshine, but it must be remembered that the butterflies require plenty of air as well as sunshine, and that they can have too much of the latter.