CEYLON BRANCH.

ON THE FORMATION OF A COLLECTION OF

LEPIDOPTERA IN CEYLON.

BY EDGAR L. LAYARD, ESQ.

(Read 3rd June, 1848.)

THE small progress which has hitherto been made towards a knowledge of the Natural History of the Island, and the total absence of all public and private collections, contrasted with the rich and extensive field which the country affords to the Naturalist, induce me to offer to the Society a few hints on the formation of a collection of Lepidoptera.

The caterpillars, or larvæ, of butterflies and moths, (or more scientifically speaking, of Diurnal and Nocturnal Lepidoptera,) may be sought for on almost every plant and shrub met in our daily walks. Morning and evening, in a tropical country, are their feeding times, and they may then be found making good use of their powerful jaws, clinging to the underside or edges of the leaves. During the heat of the day they conceal themselves in the thickest and shadiest parts of the plant, and remain perfectly motionless, till hunger and the cool breezes of evening again summon them to their pleasing labours. Some species, such as many of the grass-feeding Noctua, feed only at night, and must then be carefully sought with a lantern;

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though some may occasionally be found by pulling up tufts of grass, and examining the roots among which they lie concealed. Some of the internal feeders upon the wood and pith of trees, &c., are also active during the night, lengthening their covered galleries, which are formed from the digested particles of their food. The best means of capturing these is to watch the covered way (which may sometimes be seen of several inches in length hanging down the trunk of a tree), and, on ascertaining which is the end attached to the hole in the wood, suddenly to press the finger over it, thus stopping the return of the inmate, who is capable of a swift retrogade movement and can progress either way with astonishing speed. On lifting the web, if the larvæ is not visible, rest assured he is inside the stem far out of reach. These internal feeders are most diffiicult to rear, the surest method being to fasten a piece of strong gauze in in the shape of a bag over the aperture, and watch the natural egress of the moth. The watcher's patience, however, may perhaps be tried, as several of these species are three or four years in the larvæ and pupa (chrysalis) state. Nevertheless, as it is most probable that the discovery of the larvæ is owing to the large size of its web, it will be nearly full-grown.

Some species, again, are gregarious feeders. Some of these envelope themselves in a large mass of leaves and silk, and as they consume the foliage around them keep adding fresh materials to their domicile. Others march out in order in a wedge shape, stripping the leafy covering of the trees most completely, leaving them almost, if not entirely, bare. These larvæ are termed "processionary caterpillars," Most of the gregarious feeders are very common, and are easily found. Some of them shed their hair when handled, which, entering the uncovered skin of the face and hands, causes extreme and long irritation.

Others, again, such as some of the Limacodes, actually sting, their spines being sharp and furnished with a very pungent acid.

These larvæ are shaped somewhat like the common woodlouse" (Oniscus) with the head and feet hidden. They spin themselves little round or oblong hard cocoons, in which they undergo their transformations; and the perfect fly on emerging pushes open a little trap door, hitherto fastened by means of a natural gum, which is now melted by a strong acid secreted by the moth. All insects which spin cocoons are furnished with the abovenamed fluid, with the exception perhaps of some of the Saturnia tribe, which do not close the ends of the cocoon, but spin thick hairs over them in the shape of an "eel pot."

As my object in writing is the advancement of science and to assist those who desire to collect for the purpose of investigating the habits and peculiarities of insects, I would direct the reader's attention to the advantage, in the rearing of larvæ, of ascertaining the moth or butterfly to which each belongs. To effect this, several gauze cages should be made for the purpose of separating the larvæ. The reason of this is obvious. The larvæ of many Noctua descend into the earth to effect their final change, and the pupæ being of one uniform shape and colour, it is impossible to distinguish between them; and if all be put in the same case, they, by coming out together, make "confusion worse confounded." Let each caterpillar have, if possible, its own cage; let it be numbered and sketched; write down the name of the plant on which it feeds, with the dates of its entering into and emerging from the pupa state. These notes will not occupy much time, and, if not valuable to the observer, may, if properly and carefully kept, be of great service to a scientific man.

Butterflies and the larger moths and Sphingidæ require a large roomy box to expand their wings in on first emerging; they also require to creep with facility up the sides of the cage, that their bodies and wings, by hanging down, may stretch and harden. The very act of creeping upwards forces the fluids. - from the body (which may be seen alternately contracting and

expanding) into the nervures of the wings. The common large Saturnia, feeding on cinnamon, requires six or eight hours to harden it for flight.

The bottom of the breeding cage should be furnished with a zinc tray about three inches deep-zinc, as it does not corrode, is preferable to iron or tin; fine earth and rotten wood, well mixed together, should be laid in the tray, and over this a layer of damp moss. Into the moist earth a branch of the larva's food should be stuck to keep fresh; the oftener the leaf is changed the better; once a day at least is absolutely necessary to obtain fine full-grown specimens. Light and air also are required. The cages are best swung from the ceiling by a pulley, to facilitate the drawing up and down; they are thus secure from ants and rats and children's fingers; native servants also are too fond of meddling. Larvæ may be collected from shrubs and trees by placing a sheet or table cloth under the branches, and beating them with a long stick. An umbrella with a hooked handle makes a good portable substitute, and is otherwise useful. This plan however of beating for caterpillars is attended with much inconvenience in this country from the showers of ants which fall from each blow. Some larvæ form themselves moveable domiciles, which they never quit, except in the winged state. These tribes consist of Oikticus, Cryptothelea, Psyche, and the numerous Tine; these latter are more familiarly known by the name of "clothes' moths." The first fabricate their dwellings of pieces of stick laid lengthways, and as they increase in size they open one side of their habitaculum between two bits of stick, and let in another of proper size and length, which by means of their strong jaws they detach from the plant on which they are feeding. The second tribe are smaller and more delicate, using in the fabrication of their dwellings. small pieces of leaves and the cast skin of their own heads. The third, more delicate still, simply weave their own silk. These three species are the most remarkable in their natural