Directions for Collecting and Preserving Insects Part 4

_The Umbrella Net._--A very convenient form of net for both sweeping and for use in place of an umbrella for beating has been devised by Dr.

George Marx. (See Fig. 53.) It is constructed from an old umbrella, as follows: To the handle of the umbrella are attached two steel rods working on hinges at the apex of the umbrella, as do the ordinary umbrella ribs, and attached to the sliding piece of the umbrella in the same manner, as shown at _a_. These rods should be about 2 feet long.

When the sliding piece is pushed up and caught behind the spring clip, as shown at _b_, a circular loop is formed giving the framework for the net. The latter, which should be comparatively shallow, is made of stout muslin and sewed to the frame, as in the ordinary sweeping net. The enlarged drawings _c_ and _d_ ill.u.s.trate clearly the manner of constructing the frame. The advantage of this net is its convenience in carrying and its general usefulness, taking the place of both the umbrella and the sweeping net. When not in use the frame is allowed to a.s.sume the position shown at A, and the net may be wrapped about the frame and the whole inserted in an ordinary umbrella cover.

_The Sieve._--This useful aid to good collecting has not been generally employed by American entomologists. It facilitates the finding of small insects living under old leaves, in moss, in decayed trees, in fungi, in ants' nests, or in the ground. Any ordinary sieve about a foot in diameter and with meshes of about one-fifth of an inch will answer, though for durability and convenience of carriage one made of two wire or bra.s.s rings and muslin (Fig. 54), as follows, is the best. The ends of the wire netting should be bent around the ring so as not to project.

A piece of common muslin about 1 foot wide and long enough to go around the circ.u.mference of one of the rings is then sewed together so as to form a kind of cylinder or bag without bottom, and the upper and lower rims of this bag are then sewed on around the two rings. The whole instrument thus forms a bag, the top of which is kept open by the simple wire ring, and the bottom is closed by the second ring covered with the wire netting. After choosing a suitable locality a white cloth is spread as evenly as possible on the ground; the collector then takes the sieve, places therein two or three handfuls of the material to be sifted, returns to his cloth, and, holding with his right hand the lower ring and with the left hand the upper ring, shakes the sieve over the cloth.

The larger particles and specimens are retained in the sieve while the smaller fall through the meshes on to the cloth. Care must be taken that the siftings form an even and thin layer on the surface of the cloth, so as to be easily examined from time to time. If the locality is favorable many insects will be seen at the first glance crawling or running about, and these can easily be picked up by means of a moistened brush, or with the forceps. Many other insects, however, either feign death or, at any rate, do not move until after the lapse of several minutes, and the proper investigation of a single sifting often requires much time, and patience will be more fully rewarded here than in any other mode of collecting.

[Ill.u.s.tration: FIG. 54.--The sieve. _a_, wire netting (original).]

The size of the wire meshes given above is best adapted for sifting the fragments of old decayed trees, which furnish the most frequent material for the use of the sieve, but for sifting ants' nests, soil, etc., a sieve with smaller meshes is desirable.

The sieve is indispensable to the Coleopterist, the Arachnologist, and to the specialist in the smaller Hemiptera and Hymenoptera, but it is also useful for most other orders, many interesting species existing which can be secured in numbers only by this mode of collecting. Many Tineidae and even Noctuidae hide under old leaves, but the specimens are usually rubbed and rendered useless in the process of sifting. Many larvae and pupae can, however, thus be obtained.

If the locality chosen for sifting prove to be a good one, it pays to put the sifted material in a small sack and to carry it home where it can be investigated at leisure, and with a greater thoroughness than is usually possible outdoors. This sack can be easily arranged to be attached to or drawn over the lower ring of the sieve, so that the sifting can be done directly into the sack.

As a rule it may be said that very dry places are least productive, while more or less moist places are apt to furnish a rich harvest. Old wet leaves lying immediately along the edges of swamps, or wet moss, harbor many interesting insects, but such wet material is sifted with difficulty.

The sieve can be used with great advantage at all seasons of the year, but more especially late in fall or early in spring, when so many species are still hibernating.

_The Chisel._--For securing the many insects living or hiding under bark of dying or dead trees an instrument of some sort is indispensable, as, in most cases, the bark so firmly adheres to the wood that it cannot be torn off with the hand. A stout pocket-knife will do good service, but far better is a common chisel of medium size and with a short handle.

This chisel is also useful as an instrument for digging in the ground or for investigating the interior of partly decayed logs.

_The Trowel._--Aside from the fact that many insects enter the ground for the purpose of hibernation in various stages, there is a rich subterranean life to be found during the summer. There are many burrowing Coleoptera; many, if not most, ants construct subterranean nests; the number of other fossorial Hymenoptera is very large, and there are also various burrowing Orthoptera and many Lepidopterous larvae which hide in the ground during the day. Some instrument for digging in the ground is therefore of great importance, and while, as stated above, the chisel will answer this purpose if nothing else be at hand, yet there are other instruments which perform the work much quicker and more thoroughly. The most available instrument is a rather small steel trowel, such as can be had at the hardware stores in a great variety of patterns, and which can be carried on excursions without much inconvenience. One with a long and narrow blade, made very stout, I have found very useful, though somewhat awkward to carry.

[Ill.u.s.tration: FIG. 55.--The collecting tweezers.]

_The collecting Tweezers._--In the picking up of specimens and transferring them into the various bottles, vials, or boxes, the trained collector will gather by hand the most delicate specimens without injuring them. Yet this labor will be greatly facilitated by the use of the tweezers or the brush. The former is a small, light pair of forceps, made of steel or bra.s.s. It should be as pliable as possible, and the tip should be narrow and rounded off and not pointed. It may be either straight or curved at tip, according to individual preference.

[Ill.u.s.tration: FIG. 56.--Pinning forceps.]

[Ill.u.s.tration: FIG. 57.--Pinning forceps.]

Suitable tweezers may be obtained at the larger hardware stores or of watchmakers. Excellent tweezers made of steel (see Fig. 55) are sold for about 40 cents a pair by Codman, Shurtleff & Co., Tremont street, Boston, Ma.s.s. Aside from their utility in picking up specimens from the collecting cloth or the umbrella, the tweezers are indispensable for extracting insects from cracks, or holes in timber, or from their burrows in branches and stems of plants, or from places whence it is impossible to dislodge them by hand. The larger "collecting forceps,"

sold by various dealers, do good service in certain emergencies, as when large scorpions or other very large and ferocious insects are to be secured.

[Ill.u.s.tration: FIG. 58.--Pinning forceps for Lepidoptera.]

For the handling of mounted insects various special forceps are employed, a number of styles of which are shown at Figs. 56-8.

_The Brush._--A common camel's hair brush, of smaller or larger size according to individual preference, is useful for picking up very small or soft-bodied insects. For this purpose the brush is slightly moistened with saliva, and the tip brought in contact with the specimen, which then adheres to the brush, so that it can readily and without injury be transferred to the collecting bottle or box. The brush is indispensable also for preparing small specimens for the cabinet. If taken into the field the handle of the brush should be of a bright color, otherwise the brush is often lost.

[Ill.u.s.tration: FIG. 59.--The Fumigator. (After Kiesenwetter).]

_The Fumigator._--This is not used by American collectors, but there are several patterns sold by European dealers. It is intended to smoke out specimens that hide in otherwise inaccessible places, _e. g._, cracks in the ground, holes in hard wood, etc. The accompanying figure and the following description of a fumigator are taken from Kiesenwetter. A common smoking-pipe mouthpiece (Fig. 59, _a_) with flexible rubber joint (_b_) is attached to the cover (_c_) of a very large smoking-pipe head (_d_). To the mouth (_e_) of the latter a rubber hose (_f_) is attached, which has a convenient discharge at its end (_g_). The pipe is then filled with tobacco, and the latter ignited by means of a piece of burning tinder placed on top; the cover is then screwed on, and the smoke can be directed to any desired point by blowing air through the mouthpiece. The smoke from a common pipe or cigar is often useful. In sifting in cold weather a puff of tobacco smoke gently blown over the debris on the collecting cloth will induce many specimens to move, which otherwise "play possum" and could not be observed; and, further, tobacco smoke blown into holes and cracks in timber by means of an improvised funnel made of a piece of paper will be the means of securing many rare specimens.

_The Haversack._--In order that the above-mentioned instruments and the various bottles, vials, and boxes which are needed for the preservation of specimens may most conveniently and with the least impediment to the collector be carried along on excursions, a haversack is indispensable.

This is made either of leather or, still better, of some waterproof cloth, and should contain various compartments of different sizes; one for stowing away the nets, the sieve, and the larger instruments, and several smaller ones for boxes and vials--the whole so arranged that each desired object can readily be taken out and that nothing will drop out and get lost. The haversack is slung across the shoulders by means of a leather strap, and a full field outfit need not be very heavy nor seriously interfere with free bodily movements.

Many of the smaller objects are most conveniently carried in the pockets of the coat, which acquires, therefore, some importance to the collector. The coat should be of some durable stuff and provided with many pockets, so arranged that in stooping nothing falls out of them.

_The Lens and Microscope._--In the examination of the minuter forms of insect life the naked eye is not sufficient, and a hand-lens, or, for more delicate work, the compound microscope will be found necessary. I had, in my early experience, some difficulty in getting a satisfactory hand-lens, and the use of a poor hand-lens in time injures the eyesight, as I know by a year's rather disagreeable experience. For a hand-lens the achromatic lenses formerly manufactured by A. K. Eaton, of Brooklyn, N. Y., and now made by John Green, 35 Liverpool street, East Boston, Ma.s.s., are most excellent in workmans.h.i.+p and are satisfactory in every respect. A very good lens can also be purchased of any of the leading manufacturers of microscopical apparatus in this country. The kind of compound microscope to be purchased will depend upon the nature of the work of the investigator. Very serviceable instruments are made by J. W.

Queen & Co., Philadelphia, Pa., and by the Bausch & Lomb Optical Company, of Rochester, N. Y., and others. The German microscopes are in many respects superior to those of American make, and if one has sufficient means, I would recommend the purchase of one of the better instruments of Zeiss's manufacture, which may be obtained either direct from the manufacturers or through Queen & Co., or from the Boston Educational Supply Company. Microscopic material, including slides, cover gla.s.ses, instruments for mounting, mounting media, staining fluids, etc., may be obtained of either of the firms named above.

Having thus indicated somewhat fully the general methods of collecting, and the paraphernalia most desirable in collecting, it will be well to go still further into detail, and in connection with the different orders give some more specific information that will be valuable as a guide not only to the general collector, but to the specialist.

COLLECTING HYMENOPTERA.

The insects of this order, including Bees, Wasps, Ants, Ichneumon-flies, Gall-flies, Saw-flies, and allied insects have always been of unusual interest both to entomologists and non-entomologists on account of their diversified and peculiar habits. In abundance of species they exceed perhaps even the Coleoptera. In general they are day fliers and always to be found in abundance on bright days about flowers. The best season for collecting is in early spring, on the bloom of the Willow, Alder, and other trees. They may also be found at any season of the year, but the males of many species are only to be taken in fall. In this order, species of many groups can be most easily obtained by breeding. This includes the gall-making family, Cynipidae, and the parasitic families Chalcididae, Proctotrypidae, Ichneumonidae and Braconidae. The Chrysididae and certain other less important families are also parasitic, but are more easily obtained by general collecting. The implements necessary for collecting Hymenoptera are the sweeping-net and the beating-net. Many rare forms of the smaller parasitic families may be obtained by sweeping the gra.s.s and foliage of all sorts. The Proctotrypidae may be collected in quant.i.ty by sifting leaves and rubbish collected in the woods. Mr.

William H. Ashmead, who has made an especial study of this group, finds winter sifting profitable. Dried leaves and rubbish are sifted, the finer portion being retained and transferred to a bag. When a sufficient quant.i.ty is collected it is removed to a warm room. Many hibernating species are taken in this way, and, revived by the warmth, are easily noticed when the material is spread on white paper.

[Ill.u.s.tration: FIG. 60.--A Saw-fly (Nematus ventralis). _a_, _a_, _a_, young larvae; _b_, full-grown larva; _c_, coc.o.o.n; _d_, adult; all slightly enlarged.]

On account of the interest attaching to a knowledge of the various hosts of parasitic insects the collector should always aim to obtain the latter by breeding as much as possible. This can easily be done by keeping a lookout for larvae of all sorts which give evidence of being parasitized. The larvae of Lepidoptera found late in the fall are very apt to be parasitized, and should be collected and kept over the winter.

The parasites will emerge throughout the winter season and in the early spring. Such larvae will be found on the trunks of trees, in the crevices of the bark, and the coc.o.o.ns of parasites will also be found in similar situations.

The Tenthredinidae (Saw-flies) are not so often found about flowers but usually remain in the vicinity of the food-plant of the larva, and may many of them be collected by sweeping. The larvae of this family are in many cases difficult to breed, as most of them are single-brooded, and it becomes necessary to carry the larvae over the winter.

The Gall-flies, Cynipidae, are the easiest of the families to collect, because of their abundance and because of the ease with which they may be reared. Their galls occur in enormous variety on oaks of various species and also upon brambles and certain common weeds. These should be collected when mature and be kept in gla.s.s jars. The Gall-flies and inquilinous and parasitic species may thus be easily obtained, the former appearing at particular seasons and the latter emerging from the galls at all seasons of the year, and sometimes continuing to escape for a period exceeding two years.

One of the most interesting families in this order is the Formicidae, which comprises the true ants. In the case of these insects isolated specimens should not ordinarily be collected, and it is especially desirable to collect the species from colonies so that the three forms (males, females, and workers) may be obtained together. This holds also in the case of the social wasps and bees, but the different s.e.xes of the latter may be collected in a season's collecting about flowers, the females and workers in early spring and the males in the fall.

[Ill.u.s.tration: FIG. 61.--An Ichneumon (_Ophion_).]

The Uroceridae or woodborers are to be found only about trees in which the larvae breed. They may frequently be taken about tree trunks, or burrowing with their long gimlet-like ovipositors into the trunks of trees to oviposit. Breeding is also a satisfactory method of obtaining these insects.

Some special methods of collecting Hymenoptera may be briefly outlined.

In the case of the social bees, particularly b.u.mble-bees, and also the smaller wasps and yellow-jackets, a very satisfactory method of collecting consists in first stupefying the insects in the nest by introducing a small amount of chloroform, benzine, or bisulphide of carbon. This should preferably be done in the late evening, after all the insects have come in for the night. The nest may then be opened and examined without any danger of being stung, and the different forms may thus easily be obtained, together with any rare parasitic or inquilinous insects. In the case of the nests of Bombi this is the best method of obtaining the inquilinous Apathus species.

On account of the danger of being stung, and also on account of the extremely quick flight of these insects, the removing of Hymenoptera from the net is not always an easy task, and in many cases rare specimens escape. One method of avoiding the danger of being stung is to have the collecting net constructed with an opening at the bottom which, during the sweeping, is tied with a string. When a sufficient quant.i.ty of insects is obtained they are, by a few quick motions, driven to the bottom of the net, and the net is then seized just above the insects with the hand, the folds of cloth preventing the insects from getting to the hand, so that there is little danger of being stung. The lower end is then carefully untied and inserted into a wide-mouthed bottle, and the contents of the net shaken out into the bottle. After the catch is stupefied the vial may be turned out and the undesirable material discarded. A second method consists in the use of an ordinary sweeping-net of light material. A quant.i.ty of Hymenoptera are collected from flowers and driven to the bottom of the net, and secured as in the preceding method. The portion of the net containing the insects is then, by means of a pair of forceps, thrust bodily into a large collecting bottle. After a few minutes the insects are stupefied and may be readily examined.

[Ill.u.s.tration: FIG. 62.--The Little Red Ant (_Monomorium pharaonis_).

_a_, female; _b_, worker enlarged.]

COLLECTING COLEOPTERA.

GENERAL DIRECTIONS.--Owing to their hard outer skeleton, Coleoptera can be collected, handled, and preserved with greater safety and with less trouble than most other orders of insects. From this fact, and from their very great diversity in form, Coleoptera have, next to the Lepidoptera, always been favorites. As a consequence, there are now more species described in this than in any other order, and in the large museums they are much better represented than other insects. This rich material has been studied by numerous and competent specialists, and the cla.s.sification of Coleoptera is at present more advanced and more accessible than that of the other orders. This fact gives stimulus to neophytes, and though the literature of our North American fauna is much scattered and we are still in want of comprehensive works (with the exception of the general "Cla.s.sification" by Drs. Le Conte and Horn), yet, except in a few hitherto neglected families and smaller groups, the species are fairly well worked up.

On the other hand, our knowledge of the earlier states of Coleoptera is yet very imperfect as compared with the Lepidoptera. Coleopterous larvae are, with few exceptions (notably Coccinellidae and some Chrysomelidae), much more difficult to find and rear, and their distinguis.h.i.+ng characters are more difficult to study. The few comprehensive works on Coleopterous larvae that have been published are based on rather scant material and none of them deal with the North American fauna.

[Ill.u.s.tration: FIG. 63.--A Ground-beetle (_Calosoma calidum_). _a_, larva; _b_, adult.]

Coleoptera occur in all climates and in all localities. Species are known from the highest northern lat.i.tudes ever reached by man, and in the tropics they occur in an embarra.s.sing richness of forms. They are found in the most arid desert lands, in the depths of our subterranean caves, and on our highest mountains up to the line of eternal snow. The open ocean and the open water of our Great Lakes are the only regions free from them. As a rule, the number of species gradually increases from the Arctic regions toward the tropics, but it would be difficult to decide, speaking of North America, whether or not the fauna of the Middle States is poorer in the number of species than that of the Southern States; or whether the beetles of the Atlantic slope outnumber those of the Pacific States or those of the Central region. On the Pacific slope the influence of the seasons on insect life is greater than on the Atlantic slope. While in the latter region a number of species may be found the whole year round, there is, in the more arid regions of the West, an abundance of insect life during and shortly after the rainy season, with great scarcity during the dry season, except, perhaps, on the high mountains.

Few persons have had a more extended experience in collecting Coleoptera than Mr. E. A. Schwarz, one of my a.s.sistants, and the following account has been prepared by him at my request and is given _in extenso_.

WINTER COLLECTING.--There are more species of Coleoptera hibernating in the imago state[3] than in any other order and winter collecting is therefore most profitable in many respects. For instance, great swampy tracts which are inaccessible in the summer season harbor an abundance of rare Coleoptera, which either can not be found in summer time or are found at that season with the greatest difficulty. At the approach of winter, however, all or most of these species will leave the swamp and seek drier ground, where they hibernate under old leaves, under bark of trees, or in rotten stumps near the edge of the swamp. Such places will, therefore, give a rich harvest to the Coleopterist late in the fall, during warm spells in midwinter, and in very early spring. If the temperature is below the freezing point, or if the ground is frozen hard, no winter collecting should be attempted, first, on account of sanitary considerations, and also because the Coleoptera then retreat more deeply into the ground and can not be found so easily as when the ground is free from frost. Other good collecting places in winter are the acc.u.mulated old leaves along the edges of forests or under the shrubbery along water courses, thick layers of moss, and the loose bark of dead or dying trees, and, finally, also under the bark of certain living trees, _e. g._ Pines, Sycamore, Sh.e.l.lbark Hickory. Digging in the ground at the base of large trees or rocks also yields good returns. The only instruments necessary for winter collecting are the sieve, the chisel, and the trowel.