Fourth Archbold Expedition to New Guinea 1953 Territory of Papua
Page 100
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Transcription
side of the specimen. It is read by turning the insect over. The legs and antennae of a mounted insect should be neatly arranged, as close to the body as you can get them without hiding their characters, which are often used in making a determination. If the appendages refuse to remain in the attitude which you wish them to assume, drive the pin into the pinning block until the insect's body almost rests upon it. Then bring the appendages into position and fasten them with pins, as shown in fig. 9. If one pin does not suffice to secure a member, a pair crossed above or below it will often do so. Sagging abdomens may also be corrected by this method. The exceedingly attenuated abdomens of Dragon-flies will be more durable if each is rein- forced with a fine broom straw or piece of wire. This should reach from the end of the abdomen well into the thorax. It will show least if you remove the abdomen from the body, insert the support from the thoracic end, and join the pieces by means of a little glue and the projecting end of the reinforcement thrust into the thorax. The practise of pinning Odonata is giving way, among serious students, to that of storing the specimens in individual cellophane envelopes. Specimens which have been arranged on a pinning block should be allowed to set before they are re- moved. This may require several hours or several days and can be determined only by experiment. As soon as a specimen has been pinned or, if it has been set, as soon as it is dry enough to remove from the pinning block, the pin label or labels should be attached. To do this, lay the label on the pinning block and drive the pin through it for the proper distance. The first label should be about half an inch above the point of the pin, a second label far enough below the first to be read without difficulty. Unformity in the height of the labels adds to the ap- pearance of a collection, and may be assured by means of a pin gage. When using such a gage, as shown in fig. 3, the specimen being a small one requiring four labels, the locality label will be placed by hole 1, the collectors label by hole 2, the observations label by hole 3 and the identity label by hole 4. With thicker specimens or those requiring fewer labels, the locality label will most often stand in position 2. In choosing the exact spot on a label through which to thrust a pin, consider the size and shape of the specimen. If it is smaller than the label, let the label extend beyond it as evenly as possible in all directions. If the specimen is larger, place the label as nearly centered under it as you are able. Insects which have been mounted with wings extended at the sides require the label to be pinned in the middle with its top edge toward the head of the creature, so that the label is read from behind. Long, thin species call for a label parallel to the body's length with the top to the insect's right, the label being read from the left. If the left wings only have been spread, as they often are in grasshoppers and some other kinds of insects, the label must be pinned near the right side and extend under the wings at the left. Small insects mounted on points as de- scribed below also require a label pinned at the right end. The objects of all this are to save space and to make the collection look neat. POINT MOUNTING Of the several methods devised for mounting hard- bodied species too small for pinning, the most satisfactory is to glue them onto points. These are small, narrow slips of stiff paper with an insect pin through one end and an insect at the other. To make them, use a straight strip of paper 3/8" wide, cutting it into triangles or quadrangles by a series of diagonal snips as shown in the diagram at the top of fig. 10. At the base these should not exceed 1/6" in width; at the tip they may vary from nothing to the full width of the base. A broad attachment is more secure than a narrow one and some species are roomier than others. If your catches include many small insects, make up a supply of these points in advance. Fig. 10. The cut and use of points for mounting small insects. A. An ant, top and rear views. B. A beetle, top and rear views. The point is attached to the right side of the specimen so that when the creature is headed away from you the point extends to the left of the pin. The precise manner in which the point is applied will vary with the shape of the specimen, as illustrated in fig. 11. Most beetles, like "A," are rather flat on the bottom. To mount one of these, place the relaxed specimen, bottom up and head away from you, on a pinning block or sheet of cork. Separate the second and third legs of the right side, which will be at your left, so as to leave as broad a space as possible for the attachment of the point. If the point is glued to the legs, it is likely 6