Directions for Collecting and Preserving Insects - LightNovelsOnl.com
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[3] There are a few species of Coleoptera known in Europe which belong to the true "winter insects," _i. e._ such as appear in the imago state only during winter time, but whether or not we have such species in our own fauna has not yet been ascertained.
SPRING COLLECTING.--With the first days of spring, collecting becomes a little more varied. The methods used for winter collecting can still be continued with good success. Certain spring flowers, notably Willow blossoms, will furnish many valuable species, which are not seen again during the rest of the season.
[Ill.u.s.tration: FIG. 64.--A Lamellicorn (_Pelidnota punctata_). _a_, larva; _b_, pupa; _c_, beetle; _d_, _e_, _f_, enlarged parts.]
_Myrmecophilous and Termitophilous species._--The early spring is also the best time for collecting the Myrmecophilous and Termitophilous Coleoptera. Termitophilous species have in North America hitherto been found only in connection with the White-ants (_Termes flavipes_), and the inquilinous beetles are found running among the White-ants in the colonies under stones, loose bark of trees, and more numerously in the interior of old infested trees. Myrmecophilous Coleoptera are by far more numerous in species than the Termitophilous species and are found among many species of ants which have their nests either under stones or loose bark of trees, in stumps or logs, or which construct larger or smaller hills. Upon uncovering a colony of ants under a stone, the underside of the latter as well as the galleries of the ants in the ground should be carefully examined for inquilines, which from their greater or slighter resemblance to the ants are liable to be overlooked by an inexperienced collector. If such colony of ants harbors a rare beetle the subterranean part of the colony itself should be dug out and sifted, but since from the stony nature of the ground this is not always practicable it is to be recommended to carefully replace the stone under which the colony has been found. Upon revisiting the spot again the next day or even a few hours after the first visit additional specimens of the inquilines are usually to be obtained on the stone or in the superficial galleries of the ants. Ant colonies in hollow trees and in rotten logs should be sifted and there is no particular difficulty connected with this operation. Owing to the pugnacious character of the hill-constructing ants it would seem to be a rather unpleasant task to examine a strong and vigorous colony for inquilinous beetles, but the collector must not mind being bitten and stung by the infuriated ants, and after a little experience he will find that it is not such a difficult thing after all to attack even the largest ant-hill. The only thorough way of investigating such ant-hills is to sieve the same, which can be easily done if the hill is composed of sticks and other vegetable debris. If it is built of earth or sand the process of sifting is more difficult and tedious. Another method of securing specimens of these inquilinous beetles is to place flat stones or similar objects on the surface of the ant-hill and to examine them occasionally, when the beetles will be found on the underside of the traps.
_Spring Flights of Coleoptera._--On the first really warm days of spring commences the "swarming" season of Coleoptera, when all winged species are flying about, especially toward evening. On favorable days the number of specimens and species that can thus be found is astonis.h.i.+ngly great, and this is one of the few occasions when the Coleopterist can advantageously use a light b.u.t.terfly net. The flying beetles preferably alight and rest on the top of wooden fences (especially newly made ones), on the railings of bridges, etc., where they can be easily seen and secured, or they are attracted in great numbers by the white-painted surface of buildings. This flying season lasts in the lat.i.tude of Was.h.i.+ngton from the end of April to the middle of June, but favorable days are not of frequent occurrence, since a peculiar combination of atmospheric conditions appears to be necessary to induce the Coleoptera to fly about in great numbers.
_Beach collecting._--Along the sh.o.r.es of the ocean and the Great Lakes untold numbers of Coleoptera and other insects fall at this season into the water, and, if the tides, the currents, and the winds be favorable, they are washed ash.o.r.e by the waves on the sandy beaches, where they often form windrows several inches in height and width. If the collector is happy enough to be at the right place on the right day he has then the opportunity to pick up hundreds of rare species within a very short time and without any trouble. Many of the specimens thus washed ash.o.r.e are dead and decayed, but the majority are alive and in excellent condition. This "beach collecting" affords also an excellent opportunity for the Hymenopterist and Hemipterist to secure large numbers of rare species, but favorable days are also here of rare occurrence.
_Attracting by Lights._--On the beaches, day and night flying insects can thus be captured. Away from the beach night-flying Coleoptera can best be collected at the electric lights of our cities; but, as in the Lepidoptera, not all night-flying species are attracted by the light.
Gas and other lights also attract Coleoptera, and the various "light traps" that have been devised and described can advantageously be used for collecting these insects.
_Traps._--The method of "sugaring," so important to the Lepidopterist, is by far less favorable for collecting Coleoptera. Still, certain rare Carabidae, Elateridae, and Cerambycidae are attracted by this bait, and the Coleopterist should not entirely ignore this mode of collecting. There are a few other methods of trapping certain Coleoptera. By laying out dead mammals, birds, fishes, snakes, etc., on suitable places and so that they are protected from dogs, rats, etc., the carrion-feeding Coleoptera can be found in great abundance, but a cleaner and less disagreeable method of obtaining them is to bury in the ground tin cans or gla.s.s jars so that the top is even with the surrounding ground and to bait them with pieces of meat, fried fish, boiled eggs, etc. Many Curculionidae, Scolytidae, and numerous other wood-inhabiting species can be successfully trapped in the following way: A number of branches, preferably of only one kind of tree, are cut and tied up into bundles of convenient size. The bundles are then laid on the ground in a shady place or firmly fastened on trunks of trees. When the cut branches begin to get dry they will attract many of these Coleoptera, which can then be readily collected by shaking the bundles out over the collecting cloth.
[Ill.u.s.tration: FIG. 65.--An Elaterid (_Pyrophorus noctilucus_). (From Packard.)]
_Freshets._--Freshets usually take place in springtime in most of our rivers and creeks, and furnish the means of obtaining a mult.i.tude of Coleoptera, among which there will be many species which can not, or only accidentally, be found otherwise. These freshets, sweeping over the low banks or inundating wide stretches of low land, carry with them all insects that have been caught by the inundation. Intermingled with, and usually clinging to, the various floating debris, these insects are eventually washed ash.o.r.e by the current at various points and the Coleopterist should not miss this rare opportunity, but go out to the river bank at a time when the water is still rising, or at least when it has attained its highest point. Among, or on the washed up debris, a mult.i.tude of Coleoptera of various families can be found, and the specimens can either be gathered up on the spot or a quant.i.ty of the debris be put in sacks and taken home, where it can be examined more thoroughly and with greater leisure than out of doors. A day or so after the floods have receded the washed up specimens will have dispersed and only a few will remain in the debris for a longer period. Still more profitable than the spring floods are the summer freshets, because a larger and more diversified lot of Coleoptera is then brought down by the water. A similar opportunity for collecting is offered near the seash.o.r.e if unusually high tides inundate the low marshes along the bayous and inlets.
[Ill.u.s.tration: FIG. 66.--A Longicorn (_Prionus laticollis_).]
SUMMER COLLECTING.--During the latter part of spring and throughout the whole summer, when the vegetation is fully developed, every possible collecting method can be carried on with success, so that the beginner hardly knows what particular method to use. There are stones to be turned over; old logs, stumps, and hollow trees to be investigated; newly felled or wounded trees to be carefully inspected; here a spot favorable for sifting claims attention; promising meadows and low herbage in the woods invite the use of the sweeping net; living or dead branches of all sorts of trees and shrubs to be worked with the umbrella; the mud or gravel banks of ponds, lakes, rivers, and creeks afford excellent collecting places; the numerous aquatic beetles are to be collected in the water itself; the dung beetles to be extracted from their unsavory habitations; in the evening the electric and other lights are to be visited, the lightning beetles chased on meadows and in the woods, or the wingless but luminous females of some species of this family to be looked for on the ground, and the trees and shrubs are to be beaten after dark in search of May beetles and other nocturnal leaf-feeding species which can not be obtained at daytime; and, finally, some of the rarest Scarabaeidae and some other species fly only late at night or again only before sunrise.
In view of this embarra.s.sing mult.i.tude of collecting opportunities in a good locality, the beginner is apt to be at a loss what course to pursue. Experience alone can teach here, and only an expert collector is able to decide, at a glance at the locality before him, what collecting method is likely to produce the best results, and his judgment will rarely be at fault.
It is impossible to go into details regarding the various collecting methods, just mentioned, and only a few general directions can be given regarding those methods which have not previously been alluded to.
_Collecting under Stones._--Turning over stones is a favorite method among beginners and yields chiefly Carabidae, the larger Staphylinidae, certain Curculionidae, and a mult.i.tude of species of other families.
Stones on very dry ground are productive, only early in spring or in the fall, while those on moist ground, in the shade of woods, are good at all seasons. In the Alpine regions of our mountainous districts, especially above the timber line, collecting under stones becomes the most important method, and is especially favorable along the edges of snow fields. In often frequented localities the collector should carefully replace the stones, especially those under which he has found rare specimens. The neglect of this rule is one of the princ.i.p.al causes for certain rare species having become extinct in the vicinity of our cities.
_Collecting in rotten Stumps and Logs._--Success in collecting in rotten stumps depends much upon the more or less advanced stage of decay as well as upon the situation of the log and upon the particular kind of wood. If the decay is very much advanced neither the loose bark nor the interior of the log will harbor many Coleoptera excepting a mult.i.tude of _Pa.s.salus cornutus_ and its larvae. If the decay is less advanced, but if such log is exposed to the scorching rays of the sun, it will be far less productive than a log in a shady situation. The investigation of the bark of a favorably situated log in the right stage of decay does not need any special instruction, but the decayed wood itself should be pried off with a chisel or trowel, put in the sieve and sifted on the collecting cloth. This is the best way of obtaining the numerous species of rare Micro-coleoptera of various families that inhabit such places. A "red rotten" oak or beech log is more favorable for this mode of collecting than a "white rotten" of the same or other kinds of trees.
_Collecting in dying or dead Trees._--Dying or dead trees almost always harbor a large number of Coleoptera and offer an excellent collecting opportunity until the wood becomes thoroughly dry, which usually takes place in large trees two or three years after the death of the tree, and in less time with smaller ones. The bark of such trees is the best collecting place for Cucujidae, Colydiidae, Scolytidae, Histeridae, etc., and it will be found that the shady side of the tree is more profitable than the side exposed to the sun. The numerous Buprestidae, Elateridae, Ptinidae, Cerambycidae, Melandryidae, etc., which breed in the wood can be obtained only with difficulty. Some specimens may be cut out from their holes by a skillful use of the knife or hatchet; others (especially the Buprestidae) may be found resting on or crawling over the trunk in the bright suns.h.i.+ne, while the more nocturnal species may be found on the tree toward evening or after dark, when, of course, a lantern must be used. A large proportion of the species living in the trunks of dead trees also breed in the dead branches of otherwise healthy trees from which they can be beaten into the umbrella, or where the use of the knife is more practicable than in the large trunks. The trunks of freshly felled trees attract numbers of Cerambycidae and Buprestidae and have to be carefully looked over, while the drying foliage of such trees affords an excellent opportunity for the use of the umbrella.
_Beating living Trees, Shrubs, and Vines._--The success of beating into the umbrella branches of living trees and shrubs depends on the particular kind of tree or shrub, on the condition and situation of these, and largely also upon the season. Pine trees are very productive from early in the spring to early in the summer, but much less so in midsummer and later on. Young Oak trees or Oak shrubs are much more preferred by the leaf-eating Coleoptera peculiar to this tree than the older trees. The Beech, which, next to the Oak, is the best tree for wood-boring species, harbors but few leaf-eating species. The leaves of the Chestnut are also generally not attacked by Coleoptera; still a surprising number of species can be beaten from this tree when it is in blossom. There is not a single species of Coleoptera known to live in the wood or to feed on the leaves of the Holly (_Ilex glabra_); still it will pay the Coleopterist to beat this tree when it is in bloom. Trees, shrubs, and vines in the interior of unbroken forest districts are, as a rule, unproductive, while the edges of the woods, narrow strips of hedges, and especially solitary trees are excellent collecting places.
In the Rocky Mountains, especially in the more southern sections, long stretches of mountain slopes are occasionally perfectly bare of vegetation with the exception of a few solitary, sickly-looking, and dwarfed trees, but every one of these is a veritable gold mine to the Coleopterist with his umbrella.
_Sweeping._--The use of the beating net continues profitable from spring till fall, a different set of species appearing with each season. Low and swampy meadows, meadows on the slopes of mountains or surrounded by woods, low underbrush, and herbage in smaller patches of woods are very good beating grounds. Dry and sandy meadows are less productive, but harbor usually a different set of species on account of the difference in the flora. Pastures and meadows much frequented by cattle and horses are much less productive, and where a large number of sheep are kept there is usually no chance for using the beating net, since neither gra.s.s nor specimens are left. The lawns in our parks and gardens are usually poor collecting ground on account of the limited variety of plants in such places; but the few species found there occur in enormous number of specimens. The endless stretches of our western prairies swarm at the right season (in June) with numerous Coleoptera (mostly Malachiidae, Chrysomelidae, Mordellidae, Curculionidae, etc.), provided prairie fires have not swept too frequently over the place. Fires and cattle produce a remarkable change in the flora and fauna of the prairies; many indigenous species disappear or become scarce and are replaced by a much smaller number of imported species.
[Ill.u.s.tration: FIG. 67.--A Dermestid (_Anthrenus scrophulariae_). _a_, larva, dorsal view; _b_, larva, ventral view; _c_, pupa; _d_, adult--all enlarged.]
Sweeping may commence in the forenoon as soon as the dew has disappeared; it is less profitable in the heat of the midday, but produces the best results late in the afternoon and more especially in the short interval from just before sunset until dark. At this time many rare Pselaphidae and Scydmaenidae, species of the genera _Colon_ and _Anisotoma_, and other small Silphidae can be beaten from the tips of gra.s.ses, all being species which can not, or only accidentally, be found during daytime, when they hide between the roots of plants.
_Collecting on mud and gravel Banks._--The mud or gravel banks of rivers, creeks, and stagnant bodies of water are inhabited, especially early in summer, with an astonis.h.i.+ng mult.i.tude of Coleoptera. Countless specimens of smaller Carabidae (_Dyschirius_, _Clivina_, _Bembidium_, _Tachys_, etc.) and Staphylinidae (_Tachyusa_, _Philonthus_, _Actobius_, _Stenus_, _Lathrobium_, _Trogophlaeus_ and many other genera) will be seen actively running over the mud or sand; many other specimens are hiding under the pebbles in company with other species (_Cryptohypnus_, _Georyssus_, etc.) or in little subterranean galleries (_Dyschirius_, _Bledius_, _Heterocerus_). All these beetles must be collected by picking them up with the fingers, an operation which, owing to the activity of the specimens, requires some little practice. The beginner will at first crush or otherwise injure many of the delicate specimens, the capture of which is moreover by no means facilitated by the rapidity with which most of them are able to take wing. The collector must necessarily kneel down and he must not mind getting covered with mud. A good device for driving these species out of their galleries or from their hiding places under stones or in cracks of the ground is to pour water over the banks, and this can in most cases be done with the hand.
Larger stones and pieces of wood or bark lying on the bank are favorite hiding places of certain larger Carabidae (_Nebria_, _Chlaenius_, _Platynus_, etc.), and should of course be turned over. Finally, the moss growing on rocks and logs close to the water's edge, and in which, besides other beetles, some rare Staphylinidae and the Byrrhid genus _Limnichus_ can be found, should be sc.r.a.ped off and investigated on the collecting cloth or on the surface of a flat rock, if such be conveniently at hand.
_Collecting aquatic Beetles._--The fis.h.i.+ng for water beetles in deeper water by means of the water net has already been alluded to (p. [32]), but many species live in shallow brooks with stony or gravelly bottom, where the water net can not be used. The Dytiscidae and Hydrophilidae living in such places usually hide under stones, and can in most cases be easily picked up with the hand, or a little tin dipper or a spoon will be found convenient for catching them. The species of the family Parnidae are found on the underside of rough stones or logs which are either partially or entirely submerged. They are more numerous, however, in the moss or among the roots of other plants that grow in the water.
Such plants have to be pulled out and examined over the collecting cloth.
[Ill.u.s.tration: FIG. 68.--A Tiger Beetle (_Cicindela limbata_), drawn by Miss Sullivan--enlarged.]
_Collecting at the Seash.o.r.e and on sandy Places._--A large number of species belonging to various families live exclusively in the vicinity of the ocean, some on the open beach, others along the inlets, bayous, or salt marshes, and still others on the dry sand dunes. The Cicindelae are actively running or flying about close to the water's edge and have to be captured with the b.u.t.terfly net. The remaining maritime species live hidden under the seaweed and other debris cast up by the waves, or in the sand (sometimes quite deep below the surface) beneath the debris or between the roots of the plants growing on the dunes. The majority of the maritime species do not appear before June (in the Middle States), but the collecting remains good until September.
[Ill.u.s.tration: FIG. 69.--The Beaver Parasite (_Platypsyllus castoris_), adult--greatly enlarged.]
In dry sandy places away from the seash.o.r.e, the collecting at the roots of plants is especially to be recommended, and the plants, and more especially the bunches of coa.r.s.e gra.s.ses usually growing in such places, should be pulled up and shaken out over the collecting cloth. This mode of collecting acquires a great importance in the arid regions of the West and Southwest, where, in the warm season, nearly all Coleoptera are hiding during daytime in the ground at the roots of plants.
_Collecting Dung-beetles._--The collecting of the numerous species (_Hydrophilidae_, _Staphylinidae_, _Histeridae_, _Scarabaeidae_, etc.) which live in the droppings of various animals is by no means an agreeable task. The collector should provide himself with a pointed stick and collecting tweezers, and must manage to pick up the specimens as best he can. The larger specimens are best collected in alcohol, while the more delicate species can be collected in a cleaner condition by removing the droppings and sifting the ground beneath the same. Some species hide deep in the ground beneath the droppings and have to be dug out. Summer freshets, when pasture lands are inundated, offer an excellent opportunity for collecting the dung-inhabiting species in a clean condition.
_Night Collecting._--The beating of trees and shrubs after dark is a good method of obtaining Lachnosternas and other species, and here the collector will do well to secure the a.s.sistance of a companion, who takes charge of the lantern and the collecting bottles, while the collector himself works the umbrella.
FALL COLLECTING.--From the first of August the number of species gradually diminishes, but late in the summer or early in fall quite a number of other species make their appearance, _e. g._, some Chrysomelidae, Cerambycidae, and many Meloidae. Many of these frequent the blossoms of Golden-rods, umbelliferous and other late-flowering plants.
The fall is also the best season for collecting Coleoptera living in fungi. Although puff-b.a.l.l.s, toadstools, and the numerous fungi and moulds growing on old trees, etc., furnish many species of Coleoptera also earlier in the season, yet most fungi, and more especially the toadstools, flourish best in the fall, and consequently there is then the greatest abundance of certain species of Coleoptera. Decaying toadstools are especially rich, and should be sifted, and the collector should also not omit to examine the soil beneath them.
During the "Indian summer" there is usually a repet.i.tion of the "spring flight" of Coleoptera, though on a smaller scale, and collecting on the tops of fence posts and on whitewashed walls again becomes good. The first really sharp frost causes these late species to disappear, and winter collecting commences again.
COLLECTING LEPIDOPTERA.
In this order the importance of collecting the early states and of rearing the adult insects rather than of catching the latter should, if the collector has the advancement of knowledge and the greatest pleasure in mind, be insisted upon. Collected specimens, in the majority of cases, will be more or less rubbed or damaged and unfit for permanent keeping, and will always be far inferior to freshly reared specimens.
All Lepidopterists, therefore, rely to a great extent upon breeding rather than upon field collecting. There are, however, many species of which the early states are still unknown, and these can only be taken by field collecting, and by attracting to various lights or traps. This subject, therefore, naturally falls into two categories--(1) the general collecting of the adult, and (2) collecting the early stages and rearing the perfect insects.
[Ill.u.s.tration: FIG. 70.--The Eight-spotted Forester (_Alypia octomaculata_). _a_, larva; _b_, enlarged segment of same; _c_, moth.]
_Collecting the Adult._--The implements for the general collecting of b.u.t.terflies comprise the collecting net, and in some cases the beating net, although the use of the latter will not often be called for. The Rhopalocera or Diurnals may be taken about flowers, and the best season is in the early spring. Most of them are double-brooded, and the second brood will be in the greatest abundance during July and August. They are, however, to be found throughout the summer. They are also to be looked for in the neighborhood of the food-plants of their larvae, and in the case of many species, examination of such plants affords the most satisfactory means of collecting. The food of b.u.t.terflies is almost exclusively the nectar of flowers, but strangely enough they are also attracted to decaying animal matter, and many species, including rare forms, may be taken about decaying animal matter or resting on spots where dead animals have lain, or beneath which they have been buried.
Moist spots of earth are also frequented by them, especially in dry seasons. Many of the larger b.u.t.terflies, whose larvae feed on the taller shrubs and the foliage of trees, will be found fluttering about the open s.p.a.ces in forests, but by far the larger number, as the Browns, the Blues, the Yellows, and the Whites, which develop on the lower herbaceous and succulent plants, will be found flying over fields, prairies, and gardens. Crepuscular and nocturnal Lepidoptera, comprising most of the Heterocera, the Sphingidae, Bombycids, Noctuids, etc., have different habits. The Sphingidae or Hawk Moths fly in early evening, and may be collected in quant.i.ty about such plants as the Honeysuckle, Thistle, Verbena, Petunia, etc. The Bombycids and many Noctuids also fly in the early evening, but mostly at night. The former, however, do not frequent flowers, except such as are the food-plants of their larvae, as their mouth-parts are rudimentary, and they take no nourishment.
[Ill.u.s.tration: FIG. 71.--Collecting Pill-box. _a_, gla.s.s bottom (original).]
Collecting by the aid of strong light is a favorite means for moths as well as other insects, and nowadays the electric lights in all large cities furnish the best collecting places, and hundreds of species may be taken in almost any desired quant.i.ty. In woods or in other situations they may be attracted to a lantern or to a light placed in an open window. Various traps have been devised, which comprise a lamp with apparatus for retaining and stupefying the insects attracted to the light. The common form is made by providing a lantern with a strong reflector. Under the light a funnel several inches larger than the lantern reaches down into a box or bottle containing the fumes of chloroform, ether, or benzine.
[Ill.u.s.tration: FIG. 72.--Method of holding and manipulating collecting pill-box in capturing (original).]
Mr. Jerome McNeill describes at length and figures in the _American Naturalist_, Vol. XXIII, p. 268-270, an insect trap to be used in connection with electric lights. It consists of a tin pail or can charged with cyanide after the manner of a collecting bottle, which is attached beneath the globe of the electric light.
The insects attracted by the light strike against a vertical tin screen fixed above the can and fall into a tin funnel the small end of which enters and closes the mouth of the can, and they are thus conducted into the last. A support or post in the center of the can bears a hollow tin cone, the apex of which is pierced with a number of small holes to admit light, and enters and partly closes the lower end of the funnel. The entire interior of the can is painted black and the chief light comes through the holes in the apex of the interior cone. The entrapped insects endeavor to escape by crawling up the central post towards the light coming through the small holes in the end of the cone rather than by the entrance slit about the latter and fall back repeatedly until overcome by the cyanide.
Many of the Lepidoptera will be ruined by the beetles and other insects or by their own ineffectual attempts to escape, but Coleoptera, Hymenoptera, Neuroptera, and Hemiptera are secured in satisfactory condition.
Many of the devices are very complicated and can not be described in this connection. The nocturnal species, also, fly into our houses, and this is especially the case in the country, and an open window, with a strong light reflected onto a table covered with either a white paper or a white cloth will keep one busy, on favorable nights, in properly taking care of the specimens thus attracted.
Another favorite method of collecting moths early in the evening, or as late as or later than midnight, is by sugaring. This consists in smearing a mixture of sugar and vinegar, or some similar compound, on the bark of trees or on the boards of fences, and visiting the spot from time to time to collect the moths attracted to the bait. It has been found that the use of beer or some other alcoholic liquor, as rum or brandy, with the sugar or mola.s.ses water, greatly adds to its efficiency in attracting the moths. This method of collecting moths will be found especially efficient on warm, moist, cloudy nights. The collector should be provided with a dark lantern and a good net, and a number of wide-mouthed cyanide collecting bottles. The smearing should be done just before dark, and I have always found that better success attends this method of collecting when two are engaged in it--one to hold a bull's eye lantern while the other bottles the specimens. Experience will soon teach the surest way of approaching and capturing the specimens.
For collecting Microlepidoptera, in addition to the ordinary net, some special apparatus will be found very essential. Lord Walsingham makes use of a special gla.s.s-bottomed pill-box, with which to capture specimens, and the satisfactory nature of the work done with this box, and the dexterity acquired by practice with it, I can vouch for by personal experience. These gla.s.s pill-boxes are useful, also, in admitting of the examination of specimens, so that worthless or common species can be discarded and only desired forms kept. The method of holding these boxes is ill.u.s.trated in the accompanying ill.u.s.trations.
(Figs. 72, 73.) A drop of chloroform on the bottom of the box at once stupefies the capture so that it can be taken out and otherwise disposed of.
[Ill.u.s.tration: FIG. 73.--Same, showing method of closing pill-box after the specimen is secured (original).]