Page:Encyclopædia Britannica, Ninth Edition, v. 4.djvu/667

From Wikisource
Jump to navigation Jump to search
This page needs to be proofread.
BUTTERFLIES
597

larval condition have only four prolegs, the usual number being ten, and in moving these are brought close up to the last pair of thoracic limbs, thus giving the caterpillar a looped appearance, hence the term " loopers " usually ap plied to these moths ; they then hold on by the prolegs, and releasing those in front carry the body forward until the arched appearance is gone. They thus move by an alternate process of looping and straightening their bodies. The larva) of Geometers Lave also the curious habit of fixing themselves by their hind feet to the branch of a shrub, throwing the remainder of their bodies out, and remaining motionless in this position for hours, thus exhibiting an enormous amount of muscular energy. They are all protectively coloured, and in the attitude just described so resemble the surrounding twigs as to be readily mistaken for them. Geometers are to be found in sunshine and by night, in midsummer and at midwinter, the Early

Moth (Hybemia rupicapraria) being caught in January.

5. The Pyralidina (Plate XXXI. figs. 17, 19, 20, 23) are a group of small moths readily distinguished by their long slender bodies and large forewings. One of these, Pi/ralis vitis, is very destructive to vines, and another, Pyralis farinalis, feeds upon meal and flour. The Galleridce, a family of Pyralidine moths, deposit their eggs in the hives of bees, where the caterpillars, enclosed in silken cases, devour the wax ; but the Hydrocampidai (Plate XXXI. fig. 12), which also belong to this section, are pro bably the most wonderful of all Lepidopterous insects, their larvae being aquatic, living and feeding in the water, and many of them breathing by gills similar to those of caddis- worms.

6. The Tortricina (Plate XXXI. fig. 16) include a great number of small moths exceedingly injurious to orchard and other trees. They are known as " leaf-rollers " from the habit which most of their larvae have of rolling up the leaves on which, they feed, and thus forming a shelter for themselves. The Green Tortrix (Tortrix viridana) occurs in tho larva state on the oak, to which it often does great injury by stripping the trees of their leaves in the month of June. Throughout Southern Europe the vine is liable to the ravages of another species, (Enectra pillariana, while few of our fruit trees are exempt from the occasional attacks of some species or other of the Carpocapsidce, the fruit-eating family of this group.

7. The Tineina (Plate XXXI. figs. 21, 24-, 25) contain the smallest of the Lepidoptera, and are best known as clothes moths. These clothe themselves at our expense in the warmest woollen garments, which they traverse in all directions, leaving behind a gnaAved and worn-out path, so thin and bare as to yield to the slightest pressure. They also destroy furs, hair, feathers, and many other articles of domestic economy, and are the exterminating pests of zoological museums. To them we no doubt owe the de struction of the most perfect specimen of the Dodo known, which was once preserved in the Ashmolean Museum of Oxford. By means of their maxillre these little larvas shear down the surface of various substances, and uniting the particles by means of their glutinous silk, they thus form protecting habitations, which partake of the nature of the woollen or other stuffs on which the foresight of their parents has placed them. When they themselves increase in bulk, so as to find their abodes as inconvenient as a strait waistcoat, they split them clown the middle, and interpose a piece proportioned, no doubt, to their expected as well as actual increase. They add to the length also by fresh materials ta the anterior end. The Tinea tjrandla lives in granaries, where it forms an abode for itself by enveloping several grains in a silken web. These it after wards eats.

8. The insects of the remaining group, Pterophorina, are remarkable from the peculiar conformation of their wings. Each of these organs is split longitudinally into several branches, all of them delicately fringed. In the genus Pterophora (Plate XXXI. fig. 2G) the fore wings are divided into two, and the hind wings into three branches ; while in Orneodes (Plate XXXI. fig. 27) each wing is split into six, and these when the insect is at rest are folded together after the manner of a fan.

Collection and Preservation of Lepidoptera.—Collection

Butterflies affect special localities with which it is well for and P re the collector to make himself acquainted. A suitable servatlon - hunting ground having been selected, the following apparatus is necessary : a bag-net made of gauze or some equally light material, with a wooden or metal ring and a handle, which may also be used as a walking-stick, for capturing the specimens ; pill boxes into which to transfer them from the net ; and a wide-mouthed glass stoppered bottle, into which about forty leaves of the common laurel, bruised and cut into shreds, have been previously put. Exposure for a short time to the fumes arising from these shreds will cause the death of the inmates of the pill boxes. They may also be readily killed by pressing the thumb-nail against their thorax. For " setting " Lepidoptera, which if possible should be done before the insect stiffens, entomolo gical pins are required, and these should be gilt in order to prevent the appearance of _ verdigris at the point where the pin enters the specimen ; also a setting-board, with an upper layer of cork, and having a groove in which to lay the body of the insect ; and small triangular strips of cardboard known as braces with which to set the wings. The process of drying should not be artificially hastened, as by exposure to heat the wings are certain to warp and the body to shrivel. Should the insect have stiffened before setting, or have been badly set, it can readily be softened again by placing it, as is done in the British Museum, in a shallow earthen vessel containing a layer of damp sand, and covering it with a close-fitting lid until sufficiently soft fen* resetting. Day-flying moths must be sought for in much the same way as butterflies, while nocturnal species may be regularly met with on the sallow, the honeysuckle, the lime- tree, and the ivy, when these are in flower ; and when these and similar natural sources fail, the moth-collector has in sugar and light two admirable devices for securing specimens. A quantity of the coarsest brown sugar reduced by the addition of beer and water to a syrup, and to which a little rum is added as required, is applied with a brush to the sheltered aspect of the trunks of trees on the outskirts of woods or in the neighbourhood of heaths. At nightfall the collector, lamp in hand, visits the sugared locality, and if the evening be favourable, that is, if it be warm and dull, he is almost certain to have his pains rewarded by an abundance of specimens, chiefly belonging to the fi octuina. Moths, it is well known, are readily attracted by light, and in a country or suburban house, in the vicinity of trees, a lamp placed outside an open window, which is sheltered from the wind, with another lamp in the interior of the room, will, if the night be close and dark, be almost certain to attract numbers of moths. Mr Wallace adopted this plan while collecting in Borneo, and he states that in twenty-six nights he collected 1386 moths, "but that more than 800 of these were collected on four very wet and dark nights." In towns moths may often be caught flying about lamp-posts. In preserving the larger moths, especially the Siihingina, it is necessary to slit up their stout bodies and remove the contents, replacing these with wadding or paper. The drawers of cabinets containing Lepidoptera should be provided with a layer of cork and then papered, with a small bag of camphor attached to a corner to ward off the attacks of the dust-lice,

or " mites " as they arc usually, but incorrectly, called, the