Directions for Collecting and Preserving Insects. Charles V. Riley
sweeping net (original).
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 2½ 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 illustrate 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 assume the position shown at A, and the net may be wrapped about the frame and the whole inserted in an ordinary umbrella cover.
Fig. 54.—The sieve. a, wire netting (original).
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 brass 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 circumference 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.
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 Tineidæ and even Noctuidæ hide under old leaves, but the specimens are usually rubbed and rendered useless in the process of sifting. Many larvæ and pupæ 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 larvæ 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.
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