Directions for Collecting and Preserving Insects

In mailing living specimens the essential thing is a strong box, preferably tin, made as nearly air-tight as possible. I have found it very convenient on long trips to carry with me a number of tin boxes in the flat (Fig. 127), combined in convenient packages, ready to be bent and improvised in the field. For this purpose get any tinsmith to make out of good tin a number of pieces cut of the requisite dimensions both for the bottoms and the covers, carefully cutting the corners to permit the proper bending of the sides. These improvised boxes will prove useful for keeping living larvæ with their food-plants, especially if tied up in stout brown paper to prevent any exit from the unsoldered angles. They will also answer admirably for mailing or otherwise sending specimens to their ultimate destination. In the case of larvæ a quantity of the food-plant should always be inclosed in the box.

Living specimens, especially larvæ, should be packed in tin, with a supply of their appropriate food. The tighter the box the fresher will the food as well as the specimens keep. Insects do not easily suffocate, and it is worse than useless, in the majority of cases, to punch air-holes in such boxes. Dead specimens, when not pinned, may be sent in a variety of ways. Small ones may be dropped into a quill and inclosed in a letter, or a small vial fitted into a piece of bored wood. Those which do not spoil by wetting may be sent in alcohol, provided the bottle is absolutely filled, or, what is better, in sawdust moistened with alcohol, or between layers of cotton saturated with alcohol.

The postal regulations permit the sending by mail of “dried insects * * * when properly put up, so as not to injure the persons of those handling the mails, nor soil the mail bags or their contents.” Specimens in alcohol may also be sent by mail, provided that the containing vial be strong enough to resist the shock of handling in the mail, and that it be inclosed in a wooden or papier-maché tube not less than three-sixteenths of an inch thick in the thinnest part, lined with cork or other soft material, and with a screw top so adjusted as to prevent the leakage of the contents in case of breakage. Entomological specimens are of the fourth class of mail matter, the postage on which is 1 cent an ounce or fraction thereof, the limit of weight for a single package being 4 pounds, and the limit as to bulk 18 inches in any direction. Saleable matter is also non-mailable at fourth-class rates; so that the safer method, with small packages, is to send under letter postage. It is far better, however, for long journeys, and especially for transatlantic shipment, to send by express.

NOTES AND MEMORANDA.

In the foregoing pages are given some of the more useful directions for those wishing to commence to collect and study insects. Experience will soon teach many other important facts not mentioned here, and the best closing advice I can give the novice is, to get acquainted, if possible, with some one who has already had large experience. He will be very apt to find such a person pleasant and instructive company whether in the field or in the closet. One important habit, however, I wish to strongly inculcate and emphasize: The collector should never be without his memorandum or note book. More profitless work can scarcely be imagined than collecting natural-history specimens without some specific aim or object. Every observation made should be carefully recorded, and the date of capture, locality, and food-plant should always be attached to the specimens when these are mounted. More extended notes may be made in a field memorandum book carried in the pocket or in larger record books at home. For field memoranda I advise the use of a stylographic pen, as pencil is apt to rub and efface in time by the motions of the body. The larger record book is especially necessary for biologic notes. Notes on adolescent states which it is intended to rear to the imago can not be too carefully made or in too much detail. The relative size, details of ornamentation and structure, dates of moulting or transformation from one state to another—indeed, everything that pertains to the biography of the species—should be noted down, and little or nothing trusted to mere memory where exact data are so essential. Many insects, particularly dragon-flies, have brilliant coloring when fresh from the pupa, which is largely lost afterward. The time of laying and hatching of eggs, the number from a single female, the character of the eggs, general habits, records of parasites and their mode of attack—all should be entered as observed. A great many species have the most curious life histories, which can not be ascertained except by continued and persevering observation, not only in the vivarium or insectary but in the field. It is almost impossible to follow, under artificial conditions, the full life cycle of many species like the Aphididæ, or the Gall-flies, etc., which involve alternation of generations, dimorphism, heteromorphism, migration from one plant to another, and various other curious departures from the normal mode of development, without careful field study and experiment. These studies are possible only to those who are able to frequent the same localities throughout the whole year, and can hardly be carried on by the traveling naturalist or collector.

INSTRUCTIONS FOR COLLECTING AND PRESERVING ARACHNIDS AND MYRIAPODS.

DIRECTIONS FOR COLLECTING SPIDERS.

Apparatus.—Many of the directions and methods given in the foregoing pages for the collection of Hexapods apply also to the animals named above. Little apparatus is necessary in the collection of spiders and other Arachnids. The essentials are vials containing alcohol, an insect net, a sieve, and forceps. Narrow vials without necks are best for collecting purposes, as the corks can be more quickly inserted. They should be of different sizes, from 1 dram to 4 or 6 drams, and the alcohol used should be at least 50 per cent strong and in some cases it is advisable to use it at a strength of 70 or 80 per cent. The net may be of the same construction as that used to collect insects and is used in the same way. Some arachnologists, however, use a net of a somewhat different make, which is much stronger. The iron ring is heavier and larger than in the case of the insect net, resembling in this respect the ring of the Deyrolle net. The bag is short and the handle is fastened to both sides of the ring. This net is used for beating the leaves of trees, bushes, and grass. Dr. Marx uses a net which is already described and figured under the name of the Umbrella Net (see p. 34, Fig. 52). The sieve is the same as that described on p. 35, Fig. 54, and is used to sift the spiders from leaves and rubbish, especially during winter. A mass of leaves and other material is thrown into the sieve and then shaken, the spiders falling through on a piece of white cloth, which is spread under the sieve on the ground. Many hibernating species can be readily secured in this manner. A forceps similar to that described for the collecting of hexapods should be used to capture or pick up specimens, for if handled with the fingers they are apt to be crushed, especially the smaller forms. As soon as the collecting is finished or the vial is filled a label should be placed in this last indicating place and date of collection. Egg sacs and cocoons should be collected in pill boxes and properly labeled, and if possible the adults should be reared. Both sexes should be collected and descriptive notes or drawings made of the webs as found in nature.

Time and Locality for Collecting.—The best time to collect spiders is in the early fall, during the months of September and October. The great majority of the species are then mature. Many forms, however, occur in the adult state in late spring and early summer. Numerous species may also be collected during winter, some of these hibernating under stones, the bark of dead trees, etc., and others, more particularly the small forms, under dead leaves and rubbish on the ground in woods. Other species which have hibernated may be found about the earliest flowers in spring. No particular localities can be indicated for the collection of spiders, since they occur in all sorts of places, in wooded or open regions and also in and about dwellings. Many Lycosidæ are found in dry and rocky situations and quite a number in open fields. Thomisidæ may be found on flowers. The Therididæ affect shady places, and many Epeiridæ will be found in similar situations. The Attidæ love the sun and are found very actively engaged in hunting insects on plants and dead leaves. Many species of this family will be found in cases under loose bark in winter. Evergreen trees are also quite good collecting grounds for Attidæ. The Drassidæ are ground spiders and are mostly nocturnal, hiding during the day under leaves and stones; a few forms, however, disport in the hottest sunshine. Some genera are found most frequently near water or in damp places, as Dolomedes and Tetragnatha; others in sandy places, as Micaria, Targalia.

COLLECTING OTHER ARACHNIDS: MITES, TICKS, SCORPIONS, ETC.

Other Arachnids—as mites, ticks, scorpions, daddy longlegs or harvest-men—may be collected in the same way as spiders.

The Phalangidæ (Harvest-men) somewhat resemble spiders, and are at once recognized by their extremely long legs. They occur about houses, especially in shady places, under the eaves, etc., and in the woods and fields. They are carnivorous and feed on small insects, especially Aphides. They should be pressed a little when captured to extrude the genital apparatus, if possible, and are best collected in the early fall.

The Phrynidæ are very peculiar looking animals, the anterior legs being very long and slender and the maxillary palpi very large. The genus Thelyphonus is not uncommon in the South, and is known by its oblong body, ending usually with a long, slender, many-jointed filament, from which they are called Whip-tailed Scorpions. T. giganteus is the common species. They occur in moist situations, and are carnivorous, feeding on insects and small animals.

The false scorpions, Chermetidæ, may at once be recognized by their large maxillary palpi, resembling the maxillæ of the true scorpion. They are small insects, rarely exceeding a quarter of an inch in length, and are found in dark shady places and feed upon mites, Psoci, and other small insects. A common species is represented at figure 132.

The true scorpions, Scorpionidæ, are well-known forms, and are easily recognized by their large, powerful, forceps-like maxillæ, and the long slender tail continuous with the thorax and ending with a sting, which is, in most cases, quite poisonous. They are found mostly in the Western and Southwestern States, and are dangerous in proportion to their size. The poisonous nature of the sting of these animals is, however, generally overrated, and the wounds, even of the larger species, are rarely fatal.

The Acarina or true mites are the lowest representatives of the Arachnida and include many genera and species differing very widely in habit and characters. Some of them are mere sacs, on which the mouth parts or other organs are scarcely discernible. In general they resemble spiders. The young, however, when they leave the egg, almost invariably have but three pairs of feet, resembling in this respect the Hexapods. The fourth pair is added in the later stages. They are parasitic on insects and other animals, and some of them are vegetable feeders or live in decaying vegetable and animal matter.

The Ixodidæ comprise the ticks which attach themselves to cattle, hogs, and man, and are not at all uncommon objects. These insects can be found on the animals they infest, and distinct species will be found to occur on most wild mammals. The common Cattle tick Boophilus bovis Riley, is represented at Fig. 134.

The family Orobatidæ includes a number of small terrestrial mites, which occur on the moss on trees and stones. Some species are known to feed on the eggs of insects, and the one shown in the accompanying figure, Nothrus ovivorus has been observed, by Dr. Packard to eat the eggs of the Canker Worm.

The members of the family Gamasidæ are parasitic upon animals, but chiefly upon insects. The Hydrachnidæ are parasitic also upon the aquatic insects, and also affect fish or mussels or occur on fresh-water plants.

One of the most important families of mites is the Trombidiidiæ which includes a large number of species, some of which occur in immense numbers. Most of them are vegetable feeders, but some species feed on the eggs of insects.

The genus Trombidium includes a number of the Red Mites which feed on insects in all their stages. The Locust Mite, Trombidium locustarum Riley, is one of the most interesting as well as one of the most important of our locust enemies, and will serve to illustrate the habits of the group. It differs so much in infancy and maturity that it has been referred to different genera and is known under different names. The mature form lives on the ground and feeds on all sorts of animal or decomposing vegetable matter, and wherever the ground is filled with locust eggs these afford an abundance of food and the mites flourish and multiply rapidly. In the spring the female lays 300 or 400 minute spherical orange-red eggs in the ground (Fig. 136a). From these eggs, as shown enlarged at c, d, and e (the two latter being the vacated egg shells) emerge the six-legged larva shown at b. These are mere specks and crawl actively about, fastening themselves to the locusts mostly at the base of the wings or along the upper veins. They subsist on the juices of their host. They firmly attach themselves by the mouth and increase rapidly in size, the legs not growing and becoming mere rudiments. In this form they are shown at Fig. 137a. When fully developed they let go their hold, drop to the ground, and crawl under the shelter afforded by holes in the earth or under sticks. Here, in the course of two or three weeks, they transform within the larval skin to the pupal stage shown at b, and eventually break through the old larval skin and escape in the form shown at c and d. This mature form passes the winter in the ground and is active whenever the temperature is a few degrees above the freezing point. A larger species T. giganteum Riley, also attacks locusts, while a third species attacks the common House-fly. This was formerly known in the larva state only and was referred to the genus Astoma, to which also the larval form of Trombidium was referred. I have described the adult together with the larva and pupa as Trombidium muscarum. An allied mite, Hydrachna belostomæ, attacks the large aquatic water bug, Belostoma, and has a mode of development precisely similar to that of Trombidium.

Spiders and mites thus collected may be transferred to alcohol. Dr. Marx, who has had a very considerable experience in the preservation of spiders, recommends the use of the following mixture: Glycerin and Wickersheim's fluid, 1½ ounces of each, and distilled water 3 ounces, the whole to be shaken and thoroughly mixed and added to 30 ounces of 95 per cent alcohol. Alcohol which has previously been used for preserving spiders, and which has therefore dissolved some of the fatty matters from the specimens, he prefers to pure alcohol, using with this, however, somewhat less of the distilled water. The liquid thus composed answers all demands and keeps the specimens flexible and preserves their coloring. Should the stopper become loose and the liquid evaporate, there is always sufficient liquid, water or glycerine, left in the vial to keep the specimens from drying and thus save them from destruction. Dr. Marx also prefers to use cork stoppers rather than the rubber stoppers recommended for other alcoholic material. His objection to the rubber stopper is that, in a collection in which the specimens are often used and the stoppers are frequently removed, he finds that small particles of the rubber stopper come off and settle upon the specimens as a white dust, which it is difficult to remove. This objection applies only to a poor quality of rubber, and in all other respects the rubber is much to be preferred. The colors of spiders are apt to fade somewhat if exposed to light, and the collection should therefore be kept in closed boxes or in the dark.

COLLECTING MYRIAPODA.

Centipedes and Millipedes are collected in the same manner as spiders. They live in damp places, under sticks and stones, and in decaying vegetation. They should be preserved in alcohol, and on account of their usually strong chitinous covering, precautions as to the strength of the alcohol are less necessary here than with softer-bodied specimens.

The members of this subclass comprise a number of well-marked groups. The Iulidæ are cylindrical insects and occur in moist places, as do most of the representatives of this subclass. A common form is represented in the accompanying figure. The Chiliopodæ comprise the flattened forms having many-jointed antennæ and but a single pair of limbs to each segment of the body, and are the forms to which the name centipede may properly be applied. They are predaceous in habit, live largely on living animal matter, and are very quick in their movements. Some forms are poisonous, having poison glands at the base of the first pair of legs, but the majority of the species are entirely harmless. A number of common species belong to the genus Geophilus and occur under stones and logs. The genus Scolopendra includes some of the larger species of the order. The largest known species, S. gigantea, occurs in the East Indies and attains a length of from 9 inches to more than a foot. Several species found within the limits of the United States attain a length of 5 inches or more. The family Cermatiidæ includes the very common species Cermatia forceps, which, while abundant in the South and West, occurs somewhat more rarely in the North. It is commonly found in moist situations, in houses or conservatories, and on account of its long legs and agile movements frequently creates considerable consternation. It is, however, an entirely harmless and very beneficial species, since it feeds on various household pests, including flies, roaches, etc.

TEXT BOOKS—ENTOMOLOGICAL WORKS.

COMPREHENSIVE WORKS MOST USEFUL FOR THE STUDY OF NORTH AMERICAN INSECTS.

GENERAL WORKS ON CLASSIFICATION.

HYMENOPTERA.

COLEOPTERA.

LEPIDOPTERA.

HEMIPTERA.

DIPTERA.

ORTHOPTERA.

NEUROPTERA.

MYRIAPODA.

ARACHNIDA.

AMERICAN PERIODICALS.

FOREIGN PERIODICALS.