see captionFig.78.—Ox Bot-fly (Hypoderma bovis)enlarged.(After Brauer.)
Fig.78.—Ox Bot-fly (Hypoderma bovis)enlarged.(After Brauer.)
see captionFig.79.—The Collecting Shears.(After Kiesenwetter.)
Fig.79.—The Collecting Shears.(After Kiesenwetter.)
see captionFig.80.—A Bee-fly (Anthrax hypomelas).a, larva from side;b, pupal skin protruding from cutworm chrysalis;c, pupa;d, imago—allenlarged.
Fig.80.—A Bee-fly (Anthrax hypomelas).a, larva from side;b, pupal skin protruding from cutworm chrysalis;c, pupa;d, imago—allenlarged.
see captionFig.81.—A Syrphus-fly.
Fig.81.—A Syrphus-fly.
Most Diptera frequent flowers and may be collected with a sweeping net without much difficulty. The best season is from April to June, and the bloom of the Willow, Alder, Plum, Cherry, Dogwood, Blackberry, etc., will ordinarily yield a bountiful supply of specimens and species. Parasitic and saprophytic forms may also readily be obtained by breeding, the former as in the case of the parasitic Hymenoptera, and the latter from decaying vegetable matter and fungi. The Diptera require the most delicate treatment, and the greatest care must beexercised both in collecting and handling. A light sweep net is the best implement for collecting and the contents of the net should frequently be emptied into bottles provided with blotting paper to absorb the excess of moisture. Very small Diptera should not be killed when they can not be immediately pinned, and hairy flies should never be taken from the net with the hand, but should be handled with fine forceps. A pair of special collecting shears has been used by Lord Walsingham very successfully. It is represented in the accompanying figure, and consists of a pair of screen-covered disks, between which the fly is caught. The insect is at once pinned through the screen and may be removed and transferred to a box containing a sponge soaked in chloroform. The use of this implement is especially advisable in the case of the Bee-flies (Bombiliidæ) and other hairy forms which are liable to be rubbed when collected in the ordinary net. The Gall-making Diptera (Cecidomyidæ) are of little value unless accompanied with their galls, and the aim should always be to collect the galls and rear the insects rather than the keeping of specimens taken in the course of general collecting with a sweep net. The rearing of Cecidomyidæ is, however, a delicate task, and requires considerable experience. Some knowledge of the habits of the species is very essential to success. From immature galls norearings need be expected. A good plan is to examine the galls from time to time and collect them when it is found that the larvæ are beginning to abandon them. In the case of species like the common Cone Gall-gnat of the Willow, the larvæ of which do not leave the gall to undergo transformation in the earth, it is advisable not to gather the galls until the transformation to the pupa state takes place, which, in this species, occurs in early spring. The various leaf-mining and seed inhabiting species can be treated as in the case of the Microlepidoptera.
The insects of this order may all be collected by the use of the sweeping net. Some of the families are attracted to light, as certain of the roaches and green locusts, or Katydids (Locustidæ). Our common roaches (Blattidæ) are cosmopolitan insects, and infest dwellings. Certain species are also found about ponds, under rotten logs, the bark of trees, and particularly in decaying vegetable matter. In the tropics the species are very abundant, but aside from the domestic forms, they occur rarely in northern latitudes. The collection of the egg-cases (oötheca) is important as they furnish many interesting characters. The Mantidæ, of which the Preying Mantis (Phasmomantis carolina) is a type, are sluggish, carnivorous insects frequently found about houses and may best be collected by general sweeping of vegetation. The Phasmidæ or Walking-sticks are herbivorous and may be collected in the midst of vegetation by sweeping or by the hand. The crickets (Gryllidæ) frequent, for the most part, moist situations. Certain forms, like the Mole-cricket and the Jumping Water-crickets (Trydactylusspp.), burrow in moist soil and occur in numbers near the edges of ponds and water courses. The katydids and locusts are abundant on low shrubs or trees and in pasture and meadow land, but are most numerous in the somewhat dry, arid regions of the West. Most of these insects mature in late summer and fall and should be collected at thisseason. The Forficulidæ or Earwigs are very odd-looking insects, resembling somewhat the Rove-beetles (Staphylinidæ), and are provided with a prominent anal forceps. They are very rare in the United States, are nocturnal in habit; and, flying about at dusk, may be attracted to light or may be secured by sweeping after nightfall. They feed on flowers and fruit.
see captionFig.82.—A blind Cricket (Hadenalcus) from Mammoth Cave. (From Packard.)
Fig.82.—A blind Cricket (Hadenalcus) from Mammoth Cave. (From Packard.)
As indicated in the preliminary outline of classification, this large order has been divided into many orders by later entomologists. It has also been divided, as indicated, into two grand divisions, the Pseudoneuroptera, comprising those insects with incomplete transformations, and the Neuroptera proper, comprising those insects whose metamorphoses are complete. It will be convenient to discuss these insects under these two heads.
see captionFig.83.—ASpring-tail(Degeeria lanuginosa).
Fig.83.—ASpring-tail(Degeeria lanuginosa).
see captionFig.84.—A Mallophagan(Trichodectes latus).(After Denny.)
Fig.84.—A Mallophagan(Trichodectes latus).(After Denny.)
Pseudoneuroptera.—Spring-tails, Bird-lice, Stone-flies, White-ants, Dragon-flies, May-flies.
The Spring-tails, Fish-moths, etc., representing the primitive stock from which the higher forms have developed, have a varied habit and hence are to be found in divers situations. The Spring-tails (Collembola, etc.), occur in damp and moist places, usually in immense numbers. The Fish-moths and Book-mites are common household pests, but also occur outdoors under logs, boards, bricks, and rubbish of all sorts. In houses they feed on the starch paste beneath wall-paper and also on the starch in bookbindings and other domestic articles. They may be collected at all seasons and a sieve is the only implement necessary.
see captionFig.85.—b, a May-fly(Palingenia bilineata);c, its larva;a, a Caddis-fly(Macronema zebratum).
Fig.85.—b, a May-fly(Palingenia bilineata);c, its larva;a, a Caddis-fly(Macronema zebratum).
see captionFig.86.—A Dragon-fly (Libellula).(From Packard.)
Fig.86.—A Dragon-fly (Libellula).(From Packard.)
The Bird-lice or Mallophaga may be collected at all seasons on birds and mammals. A number of species infest domestic animals, horses, cattle, etc., but the majority of them can be found only by the examination of domestic fowls and wild birds. The Stone-flies (Perlidæ) are found in the neighborhood of water courses and ponds, are very sluggish in flight, and easily captured with the sweep-net. They are also attracted to light. The Psocidæ are a small family of certain degraded wingless forms, comprising the Book-lice, which, as the name implies, infest books, feeding on the starch of the binding. Others have ample wings and closely resemble large Aphides. They occur on the trunks of trees and on foliage, and feed on lichens and other dried vegetable matter. They are gregarious in habit and frequently occur in immense numbers together. In the case of the Termitidæ or White-ants, their abundance renders their collection an easy matter. Effort, however, should be made to discoverthe different forms, the females and soldiers as well as the workers. The former may be found in rotten tree trunks, but are very rarely met with. In the tropics many species occur and construct curious nests, either attaching them to the boughs of trees or building them in the form of pyramids on the ground. The Dragon-flies (Libellulidæ,) are collected in the same way as the Diurnal Lepidoptera. They are very swift flyers, and are practically always on the wing. Their collection requires some degree of skill in the use of the net. A good method consists in visiting, in the early morning, water courses in which the larval and pupal states are passed, and capturing the adults just as they issue from their pupal skins at the edges of the pond or stream. In cold weather they are less active and may frequently be found clinging to trees and plants, particularly in the vicinity of their breeding places. May-flies (Ephemeridæ) occur in immense numbers near their breeding places in ponds and streams and are also attracted in large quantities to electric lights. Their collection is therefore an easy matter, but on account of the very fragile nature of these insects the utmost care must be employed in handling them. The early states of all the aquatic forms mentioned above may be obtained for breeding by the use of the dip net by dragging it forcibly against water plants.
see captionFig.87.—A Dragon-fly (Agrion).(From Packard.)
Fig.87.—A Dragon-fly (Agrion).(From Packard.)
see captionFig.88.—An Ant-lion, adult (Myrmeleon).(From Packard.)
Fig.88.—An Ant-lion, adult (Myrmeleon).(From Packard.)
Neuroptera proper(Hellgrammites, Lace-wings, Ant-lions, Caddis-flies, etc.)—Among the largest insects of this order are the Sialidæ, which includes the enormous Hellgrammite Fly,Corydalus cornutus. The larvæ of this insect are carnivorous and occur in streams, under stones, etc. The adults may be collected in neighboring situations and are also attracted to light. The Lace-wing flies (Chrysopa), Ant-lions, etc., are carnivorous as larvæ, and occur, the former among the Aphides which infest various plants and the latter at the bottom of pits in loose,sandy soil. The adults may be obtained by general sweeping and are also attracted to light. The most interesting insects of this order are the Caddis-flies, on account of the peculiar and frequently very beautiful cases constructed by their larvæ, which it is important to collect. The Caddis-flies breed in ponds and lakes and the adults may be collected in such situations or at light. The larvæ may easily be reared, and should be collected for this purpose. Most of the insects named in this order are extremely delicate and require great care in handling.
Between the collecting of the specimens and their final disposition in a well-arranged cabinet, a good deal of mechanical work is necessary, involving a skill and dexterity which can be thoroughly acquired only by practice.
First Preservation of living Specimens.—Larvæ, pupæ, or imagoes, intended for rearing purposes, must be kept alive, and are best placed, after capture, in tin boxes of various sizes, according to the number of specimens to be put in each and according to the size or nature of the food plant, etc., on or in which the specimens are found, and of which a quantity must always be taken home. For larger tin boxes those known as “Seidlitz powder boxes,” described and figured below, which can be made to order at any tinner's shop, are well adapted, and smaller tin boxes of a convenient round form can be obtained of the watchmaker. The collector will find it advisable to take with him on his longer jaunts a larger tin collecting box as well as the smaller boxes, and for this purpose nothing is better than a good botanist's collecting can or vasculum. All tin boxes used for entomological purposes should be tight, and the cover should so fit that it neither drops off too readily nor closes too tightly. Larvæ of Lepidoptera and Tenthredinidæ should be placed in a box with a quantity of the leaves of the plant on which they were found. Larvæ, especially of Coleoptera, found in the earth or in decayed wood, should be placed in a box filled with such earth or wood, so as to prevent shaking or rattling about. Larvæ found in roots or stems of living plants can generally be reared to maturity only if the whole plant with a quantity of the surrounding soil is taken home, and for this purpose the large collecting box, just mentioned, is very useful. Most Coleopterous or other larvæ found under bark or in solid wood can be reared only if large sections of the wood are obtained and the larvæ are full grown or nearly so. This holds true, also, of speciesbreeding in seeds and with most leaf-mining species. The greatest difficulty is experienced with carnivorous Coleopterous larvæ, and care should be taken with such not to inclose two or more specimens in one box. Most larvæ die quickly if placed in an empty box, and this is especially true of predaceous species; so that it is always advisable to pack the box with moist soil, decaying wood, leaves or other similar substance. Aquatic larvæ should be carried in tin boxes filled with wet moss or some water plant, for, if placed in corked vials with water, they die quickly.
Killing Specimens.—Specimens not intended for rearing should be killed immediately after capture unless for each specimen a separate vial or box can be provided. If a number of miscellaneous insects are put in the same vial the stronger specimens will, in a short time, crush or otherwise injure the more delicate ones or the predaceous species will devour any others they can master. But even where the specimens are killed immediately the following rule should be observed: Do not put large and small specimens in the same vial, but provide a larger bottle for the larger specimens, and one, or still better, several, smaller vials for the medium-sized and very small specimens. The importance of this rule is recognized by all experienced collectors.
There are several methods of killing insects, each having its own peculiar advantages and drawbacks.
Alcohol.—The use of alcohol will, on the whole, prove the most satisfactory method of killing Coleoptera, many Hemiptera, some Neuroptera, and larvæ of all sorts. Only the best quality of alcohol should be used, but it should be diluted with from 30 to 40 per cent of pure water, the greatest care being taken to keep the alcohol as clean as possible. During the collecting a mass of débris and dirt is apt to be thrown into the bottle, and when this is the case the alcohol should be changed even during short excursions. At any rate, upon the return from the excursion, the specimens should be at once taken from the bottle and washed in pure alcohol in a shallow vessel. The larvæ and other material intended for permanent preservation in alcohol should be transferred to suitable vials and the material to be mounted cleansed with chloroform or acetic ether and then prepared for the cabinet. If it is inconvenient or impossible to mount the Coleoptera, etc., soon after the return from the excursion they should be washed, dried, and placed in pill boxes between layers of soft paper, or they may be replaced in a vial with pure alcohol. On longer collecting trips, lasting several days or weeks, specimens will keep thus very well, provided they are not shaken up, and this can be prevented by filling the empty space in the vial with cotton or soft paper. If the bottle is a large one and contains many large specimens the alcohol should be renewed three or four times at intervals of eight or ten days; otherwise the specimens are liable to decompose. Small and delicate specimens, if they are to be kept in alcohol, should be treated with still greater care. Upon thereturn from the excursion they should also be cleaned in pure alcohol and placed in small vials into which a very few drops of alcohol, just sufficient to keep the contents moist, are poured. The vial should be corked as tightly as possible and the specimens will keep pretty well for an indefinite time.
The drawbacks to the use of alcohol are: 1st, that all hairy specimens are liable to spoil; 2ndly, that all Coleoptera with soft integuments spread the wing-cases apart if kept too long in it. The advantage of the alcohol is that it is the simplest and least troublesome fluid for naturalists traveling in distant countries who are not specialists in entomology. Specimens killed in alcohol are also less liable to be attacked by verdigris when pinned than those killed by some other method. Rum, whisky, or similar strong alcoholic liquors may be used as substitutes where no pure alcohol can be obtained, but are not especially to be recommended.
see captionFig.89.—Chloroform bottlewith brush.
Fig.89.—Chloroform bottlewith brush.
Chloroform and Ether.—Killing with the fumes ofchloroformorether(sulphuric or acetic) orbenzine, or some other etheric oil, is often practiced and advocated by those who, for any reason, dislike the use of alcohol or object, on account of its poisonous nature, to the use of cyanide of potassium, and they are of especial value in the case of butterflies and moths, Hymenoptera and Diptera. “A small and stout bottle of chloroform or ether, with a brush securely inserted into the cork (Fig. 89), will be found very serviceable. A slight moistening through the air net will stupefy most insects caught in it, and facilitate their removal to the cyanide bottle; while a touch or two with the wet brush under the head and thorax, will kill the more delicate specimens outright, without in the least injuring them. Another way of using chloroform is by means of a small, hollow tube passed through the cork, what is called jeweler's hollow wire answering the purpose. The liquid evaporates more readily in such a bottle, and I altogether prefer the first mentioned. Some large insects, and especially female moths, whose size prevents the use of the ordinary cyanide bottles, are difficult to kill. With these, fluttering may be prevented by the use of chloroform, or they may be killed by puncturing the thorax or piercing the body longitudinally, with a needle dipped in liquid cyanide, or oxalic acid. A long bottle with a needle thrust into the cork may be kept for this purpose; but the needle must be of ivory or bone, as those of metal are corroded and eaten by the liquids. * * *
“For killing small and delicate moths which have been bred, I find nothing more handy than chloroform. They may be caught in turned wooden boxes which are kept by every druggist; and a touch of the chloroform onthe outside of the box immediately stupefies them. It has a tendency to stiffen them, however, and they are best set immediately after death.”
see captionFig.90.—Bottle withliquid cyanide.
Fig.90.—Bottle withliquid cyanide.
see captionFig.91.—The Cyanide bottlewith paper strips to give supportto the insects.
Fig.91.—The Cyanide bottlewith paper strips to give supportto the insects.
A piece of heavy blotting paper or heavy cloth soaked with chloroform or ether or benzine and placed at the bottom of a jar or bottle makes an excellent killing bottle for large-sized insects. For smaller specimens the collecting vial should be half filled loosely with narrow strips of soft paper, upon which a few drops of the liquid are poured, not so much, however, as to wet the paper. While collecting, the vial must be kept closed as much as possible. Some collectors prefer chloroform, others ether. If this method of killing is practiced with the necessary care, there is no objection whatever to it; the specimens are not wetted as they are in alcohol, and remain cleaner than those killed by any other method. The drawback is that the substances mentioned evaporate very rapidly and have to be renewed even on short excursions. On account of this great volatility, one can never be certain that all the specimens in the collecting bottle are dead after a given time and there is always some danger that one or the other of the hardier insects may regain activity. What mischief such revived specimens are capable of doing, many collectors have experienced to their sorrow. Another disadvantage of these volatile substances is that if used in too large quantities they will, in delicate specimens, especially beetles, cause an extension of the soft ligaments between the head and prothorax or between the latter and the mesothorax, and thus bring the specimen into an unnatural position, or cause the head, or head and thorax to drop off.
Cyanide of Potassium.—The method of killing which, of late years, has found most favor with collectors, is the use of cyanide of potassium. For killing large sized specimens they are simply put in what is now universally known as the “cyanide bottle.” This may be constructed as follows:
see captionFig.92.—Pocketcyanide bottle.
Fig.92.—Pocketcyanide bottle.
Take a 2-ounce quinine bottle, or still better a shorter bottle with a wide mouth; break up a quantity of cyanide of potassium into pieces ofconvenient size (about a cubic centimeter); put these pieces in the bottle so that they form an even layer at the bottom; mix in a convenient vessel a quantity of plaster of Paris with water just sufficient to make the mixture semifluid and then pour it over the cyanide so as to cover this last to a depth of about 5 millimeters. The bottle is then left open for an hour or two until the plaster is thoroughly dry. The walls of the bottle are then cleansed from particles of the plaster which may have splashed on them, and the bottle is ready for use. If not used too frequently, especially in warm weather, it will last for an entire year or longer. Bottles or vials of different sizes can be prepared in the same way, and a very small cyanide vial which can be carried in the vest pocket will be found most convenient for use on all occasions.Fig. 92represents a medium-sized chemist's test tube, converted into a very convenient cyanide bottle, in which, however, a cotton wad has been used to keep the poison in place. When the collected specimens have been removed from the bottle the latter should be carefully wiped clean with a piece of cloth or paper. The surface of the plaster soon becomes dirty and, on account of the hygroscopic property of the cyanide, more or less moist, especially during warm weather. The cyanide bottle is, therefore, not well adapted for the killing and temporary preservation of small and delicate specimens. This difficulty can be altogether obviated by placing a circular piece of blotting paper, cut to neatly fit the interior of the bottle, on the surface of the plaster. This can be renewed once a week or so, or oftener if it becomes necessary. It will frequently be advisable, also, especially in the collection of Diptera, Hymenoptera, and other delicate insects, to put a strip of blotting paper partially round the inner side of the bottle. This will absorb any moisture which may gather on the inside of the bottle and which would otherwise wet and injure the specimens. The accompanying figure (Fig. 93) illustrates a bottle arranged as described above. A similar result is attained by some collectors by partially filling the bottle with narrow strips of bibulous paper to support and separate the insects as shown atFig. 91.
see captionFig.93.—The cyanide bottlewith blotting-paper lining (original).
Fig.93.—The cyanide bottlewith blotting-paper lining (original).
For delicate specimens, also, the collecting bottle may consist of a test-tube of about the size ofFig. 92. This is half filled with loose, thin strips of soft white paper. A piece of cyanide about the size of a pea is then wrapped carefully in paper and so placed in the middle of the strips that it can not come in contact with the sides of the glass. Some prefer to pin the paper containing the cyanide to thelower surface of the cork. The latter should be rather short and tapering toward its lower end. It is longitudinally perforated through its center by a round hole just large enough to insert a goose-quill, which is cut straight at the lower end and obliquely at its upper end. By means of this goose-quill the specimens may be introduced into the bottle without taking off the cork. This form of cyanide bottle lasts for only one day's collecting, except in cold weather, and in very warm weather it is advisable to take two prepared bottles along, so that the first used can be stowed away as soon as the cyanide begins to moisten the paper strips. Most insects are quickly killed in such a bottle, but some Coleoptera must be left in for five or six hours, while others resist death for a still longer time. This is especially true of the Coleopterous families Curculionidæ, Trogositidæ, and Tenebrionidæ.
Submersion in alcohol will prove a satisfactory method of killing these or other beetles with similar vitality.
Other Agents.—Prof. E. W. Claypole has found the use of benzine or gasoline very cheap and satisfactory for killing Lepidoptera, as the largest are at once killed thereby without injury to their scales. (Can. Ent.,xix, p. 136.) He squirts it onto the specimen within the net or in the open air by means of a druggist's dropping tube. Hot water kills rapidly and leaves the specimens in good flexible condition for mounting. The heads of large insects may be held for a few moments in the water, while smaller specimens should first be thrown into a corked bottle and the bottle submitted to heat. Where the laurel grows its bruised leaves may be used in place of cyanide; they kill less quickly. The leaves of the Laurel-cherry (Prunus laurocerasus), a plant commonly grown in England for screens and hedges, are also used for this purpose.
Some collectors, with indifferent olfactory sense, moisten the cork of their boxes with creosote. Its killing power lasts for several days. A few whiffs from a cigar, when nothing else is at hand, will also kill many of the more tender insects.
Special directions for different orders.—A few brief directions for the special treatment of different orders may be given. Certain Coleoptera, notably those of the Curculionid genus Lixus, are covered with ayellowish pruinosity resembling pollen, which is of an evanescent nature, so that if the specimens are collected and killed by the ordinary methods, the pruinosity is completely lost. To preserve the natural beauty of such species it is necessary to put each specimen alive in a small vial and to kill it at once by means of a lighted match held under the vial for a few seconds. In pinning or otherwise mounting the specimen it should not be handled between the fingers.
Many Hymenoptera and Lepidoptera, especially species with yellow markings, if kept for any length of time in a cyanide bottle, will become discolored, the yellow changing to reddish, and hence such insects should not be left longer than necessary in the bottle. If care is exercised in this respect, no danger of discoloration need ordinarily be feared. The chloroform collecting bottle may be used with these insects if discoloration is anticipated. All the more delicate insects, including Hymenoptera, Diptera, the smaller Lepidoptera, and the Neuroptera, require special care in killing. Large numbers should not be thrown into a killing bottle together, and plenty of bibulous paper should be kept in the bottle to prevent moisture from accumulating and wetting and ruining the specimens. It is frequently advisable to pin Diptera, especially the hairy forms (as the Bee-flies), in the net and transfer them at once to a cigar box containing a sponge moistened with chloroform. When the collecting shears are used, the insects are always thus pinned at once, which is, in fact, the only method of securing them. This is also necessary in the case of many Lepidoptera. Delicate Neuroptera may be killed by the use of the cyanide bottle, or, preferably, placed at once in a vial of alcohol, as these insects, in many instances, cannot be kept securely if pinned or mounted. Large Lepidoptera, as the Bombycids, may be killed by pouring benzine, naphtha, or chloroform over the thorax and abdomen. These substances evaporate rapidly and do not appreciably injure the vestiture of the insects. Some collectors, in the case of butterflies, seize them dexterously between the thumb and finger, and give a sharp pinch on the sides of the thorax. This will prevent the fluttering of the insect when transferred to the cyanide bottle, and, if carefully done, the scales need not be rubbed off. It is objectionable, however, because the thorax is distorted and subsequent anatomical study interfered with, and, in the case of moths, should never be practiced, as the thorax affords important characters used in classification. Orthoptera may be killed by the use of the cyanide bottle but should be transferred at once to the vials of alcohol. If placed in a cyanide bottle, especially in the case of Locusts (Acrididæ), they are apt to exude colored juices from the mouth, so that the specimens become soiled. Hence the use of vials of alcohol is preferable, and these insects should never be thrown into vials containing delicate insects of other orders. Plant-lice, together with the plant which they infest, should be placed at once in vials of alcohol, and specimens of the Aphides, representing all the formspresent, should be mounted on slides for microscopic examination. The fixed forms of Coccids, comprising the majority of the species, require no special treatment, and the leaves, twigs, or bark on which they occur may be pinned at once and placed in the collection. The free forms are treated as in the case of plant-lice.
Under this term may be considered the preparation of insects for the cabinet.
Insect Pins.—In mounting insects for the cabinet, expressly made entomological pins should be used. These come from three different sources: Kläger pins, made by Hermann Kläger, Berlin, Germany; Karlsbad pins, made by one or several firms in Karlsbad, Bohemia, Austria; and Vienna pins, made by Miller, Vienna, Austria.[4]These three kinds of pins have each their own slight advantages and disadvantages, so that it is difficult to say which is the best. All have the disadvantage that the pinned specimens are liable to be ruined by verdigris, and to obviate this japanned (“black”) insect pins are made by Kläger and Miller. These black pins are, however, much softer than the “white” pins, and therefore more difficult to handle. A pin of 35 millimeters in length will be found most convenient for pinning all insects excepting the larger Lepidoptera and other heavy-bodied insects, for which a longer pin may advantageously be used. According to the different degrees of fineness, the pins are numbered from No. 00 (the finest in the trade) to No. 7 or 8, but the numbers used by the different manufacturers do not correspond with each other. In experience, pins of Nos. 1, 2, 3, and 4 (Kläger numbers) are more often needed than the others. The long pins of the finer numbers (Nos. 0 and 00) are difficult to handle in the collection and, for this reason, not to be recommended.
For many small insects, especially Microlepidoptera and Microdiptera, whichmustbe pinned, even the finest ordinary insect-pins are too large, and two special makes of pins are in use for this purpose. The “elbow pin” (formerly made and sold by Dr. Kuenow, of Königsberg, Prussia, Germany) consists of a piece of fine silver wire, pointed at one end, and with a coil loop at the other end, into which a longer pin (No. 3 or No. 4) is thrust. This pin is illustrated inFig. 94. Still more satisfactory are the “Minutien-Nadeln” (pins for minute insects) manufactured by Mr. Miller, of Vienna, Austria, and which consist of a straight piece (about 14mm. long) of extremely fine steel wire which is pointed at one end, and which is used in connection with a piece of pith or cork. The mode of using this pin isshown in Fig. 101. These fine and elbow pins may be obtained either “white” or japanned.
see captionFig.94.—Insectmounted on“elbow-pin.”
Fig.94.—Insectmounted on“elbow-pin.”
“Many English entomologists use short pins, very much like those of ordinary make, and my late friend Walsh never gave up the custom, and most vehemently opposed the use of what he ridiculed as ‘long German skewers.’ But the only advantage that can possibly be claimed for the short pins is that they are less apt to bend, consequently more easily stuck into the bottoms of boxes, and require less room; while, compared with the long pins, they have numerous disadvantages. Long pins admit of the very important advantage of attaching notes and labels to the specimen; render it more secure from injury when handled, and from museum pests in the cabinet; and on them several rows of carded duplicates may be fastened, one under the other, so as to economize room.”
I have seen few old collections in better condition than that of the late E. Mulsant, of Lyons, France; and he used iron wire, cut slantingly, of the requisite length—a common custom in France. These wires bend so easily and have such dull points that they require much more careful manipulation than the pins, and the claim made for them that they do not verdigris would, perhaps, be offset by their rusting in moist climates or near the sea. Silver wire or silver-plated wire is also used.
Preparation of Specimens.—Upon the return from an excursion the specimens should be prepared for the collection as soon as practicable. If they have been collected in the forenoon they should be mounted the same evening, and those collected during an afternoon or evening excursion should be mounted the following morning, or, at any rate, before they get dry and brittle. Even specimens collected in alcohol should be attended to as soon as possible.
Specimens are taken from the collecting bottle, spread out on a sheet of white blotting paper and cleaned from adhering impurities either with a soft dry brush, or, in the case of species with hard covering, by washing them with chloroform or ether or benzine where necessary. Theoretically the best way of mounting would be to pin all specimens, since the under side with its important characters then remains free for examination. Pins adapted for pinning even the smallest insects have been described above, but this pinning is such a delicate operation and requires so much time that considering the large number of small specimens that may be collected on a single short excursion it is next to impossible to carry out this method, and therefore only the larger specimens need be pinned and the smaller may be glued onto the paper points described later. If the work is done with proper care all insects can be prepared for the cabinet so that both the upper and undersurface of the specimen may be examined without further manipulation.
see captionFig.95.—Method of pinning andlabeling Coleoptera (original).
Fig.95.—Method of pinning andlabeling Coleoptera (original).
Pinning.—“Insects should be pinned through the middle of the thorax, when, as is more generally the case, this portion (the mesothorax) is largely developed. Beetles (Coleoptera) and Bugs (Hemiptera), should, however, be pinned, the former through the right elytron or wing-cover (Fig. 95), and the latter through the scutel or triangular piece behind the thorax, the pin issuing between the middle and hind legs (Fig. 96). The specimens look very pretty with all the legs neatly spread out, but for practical purposes it is better to let them dry in the natural, partly bent position. It is a saving of time and space, and the limbs are not so apt to break. The legs must also not reach too far downward or they will interfere with the proper labeling and the secure pinning of the specimen in thecabinet.Moreover, the antennæ and legs must be brought into such position that they will not obstruct the view of any important part of the undersurface. The pin should always project about half an inch above the insect to facilitate handling, and uniformity in this regard will have much to do with the neat appearance of the collection. In pinning very large and heavy insects on a No. 4 or No. 5 pin, it is a good plan to first flatten the pin by a few blows of a hammer, in order to prevent the specimen from subsequently turning round on the pin.”
see captionFig.96.—Methodof pinningHemiptera (original).
Fig.96.—Methodof pinningHemiptera (original).
In pinning specimens which have a flat or nearly flat undersurface and short legs (as in many Coleoptera and Hemiptera and some Hymenoptera,e. g.theSaw-flies) the specimens are laid on a piece of cork and held in place there with the fingers or with a forceps. The pin is then pushed through the insect at the proper point, care being taken not to strike one of the legs or coxæ, and that the pin passes through the specimen in a vertical direction.
After the pin has been pushed through the specimen it is taken out of the cork and the specimen is pushed up to its proper height. This can be done either by holding the specimen between the fingers or by placing it on the upper edge of a thick book. A piece of cardboard provided with a small hole may also be used for this purpose. The perforations in ordinary sheet-cork, or the lapel of one's coat, will answer the same purpose. In pinning Lepidoptera or Hymenoptera the specimen should lie lightly in the angle formed by the thumb and first two fingers of the left hand and the pin be carefully thrust through at the proper angle.In pinning all insects the pin should be so inserted that the insect is nearly at right angles with the pin, the posterior end being slightly depressed.
Mountingon Points.—Most insects which are too small to be pinned on a No. 2 pin may be fastened to cardboard by means of gum tragacanth, gum shellac, or any good glue. It is not always easy to determine whether to pin a medium specimen or to glue it to a triangle. Pinned specimens are more secure, and not so apt to fall or be knocked off, but they are liable to become corroded by verdigris and ultimately lost, especially in families the larvæ of which are endophytous or internal feeders. It is better to glue wherever there is doubt. A drop of corrosive sublimate added to the water in which the gum tragacanth is dissolved will indefinitely prevent its souring, but should not be used where the gum is to come in contact with the pin, as it inclines the latter to verdigris. In such cases a little spirits of camphor mixed with the gum tragacanth is best. Shellac should be dissolved in alcohol and this requires some time. This glue is not affected by moisture, and if it is desired to remove the specimens, they must be immersed in alcohol until the shellac is again dissolved.
A number of different kinds of glue are used by entomologists. The requirements of a good glue are that it be colorless, and, what is of greater importance, that the specimens adhere firmly to the paper points so that there is little or no danger of their being jarred off. Those glues which are readily soluble in cold or lukewarm water are perhaps more convenient than those which require alcohol or chloroform for dissolving. Gum arabic and gum tragacanth have the disadvantage that they are more liable to attract mites and are more brittle, so that they do not hold specimens as well as some of the liquid glues that are on the market. Spalding's glue answers a very good purpose, as also the preparation known to European entomologists as Leprieur's gum. White bleached shellac, while requiring alcohol to dissolve it, has the advantage that a very minute quantity suffices. In olden times the method employed was simply to glue the specimen by the ventral side to the middle of a quadrangular piece of cardboard, which was then pinned on a No. 3 or No. 4 insect pin. This method is still in vogue with English entomologists, but can not be recommended except for mounting duplicates. Much better are the small isosceles triangles which, before mounting the specimen, are pinned through near the base on a No. 2 or No. 3 insect pin. Only the best and finest cardboard should be used for this purpose, since that of poor quality is liable to be broken while passing the pin through it and will yellow with age. “Reynolds's Superfine Board,” which may be ordered through any dealer in artist's supplies of Devoe & Co., Fulton street, New York City, is perhaps the best for this purpose. Some of the neatest mounting which I have had done by any of my agents or assistants is by Mr. Albert Koebele, who has used mica or gelatine instead of cardboard, the objectbeing not only to show the whole of the under side of the specimen, but to obscure less of the light from the labels and to render the triangles less conspicuous in the cabinet. These have been in use in the museum collection only for the last two or three years, and whether they will eventually tend to corrode the pins is not yet settled. Mica and isinglass are also used for the same purpose. The points used in mounting may easily be cut by hand to a convenient size, say one-fourth of an inch (6–8mm) long by one-sixteenth or less at the base, and tapering to a point. The point may be narrower or wider to accommodate insects of different sizes.
For cutting these triangles or points, various forms of punches similar to the appended figure (Fig. 97) known to the trade as conductor's punches may be used, and points thus cut are to be preferred to those made by other means, on account of the greater uniformity secured.
An experienced hand, however, will cut these points very rapidly and accurately with a pair of shears, and most collectors use no special instrument for this purpose.
see captionFig.97.—Insect punch for cutting trianglesor points (original).
Fig.97.—Insect punch for cutting trianglesor points (original).
The punches mentioned may be obtained of the manufacturers[5]of such instruments at from $2 to $3. Care should be observed in ordering to state explicitly the length, width at base and point, or, what is better, to inclose sample of the size of point it is desired to cut; but above all, to state that the block of paper to be cut out is the result desired, and that the instrument should cut clean and even, with no ragged edges.
For mounting different forms and sizes the fastidious collector uses four or five sizes of points, but for all practical purposes one to cut a card point not less than 1.3mmat the base and prolonged as nearly as possible to a point, and another a trifle wider at the base, say 1½ or 1⅔mmand with a point about 1½mmin width will suffice.