Fig, 131. — Moth whose wings are developing. Fig. 132. — Moth whose wings are developed.

Memoir of Re'aumur {sur la transformation des chrysalides en papillons), show the states through which the wings of the same moth pass, before they are thoroughly developed.

Those pupos enclosed in cocoons free themselves entirely or in part from their old skin, in the shell itself; but the imago is still a prisoner. It has broken through a first enclosure; it must open itself a way through the second. How does it manage to bore through the often very solid walls of this second prison, so as to

regain its liberty? Re'aumur states that in the Lackey Moth {Bombyx neustrid) the head is the only instmment of which the insect makes use in opening a passage, the compound eyes then acting like files. These files cut the very fine threads of which the cocoon is composed, and as soon as the end of the cocoon is pierced through, the insect uses its thorax like a wedge, to enlarge the hole. It very soon manages to get its two front legs out, fixes itself by them on to the outside, and little by little emerges from its prison.

Fig, 131. — Moth whose wings are developing.

Fig. 132. — Moth whose wings are developed.

LEPIDOPTERA.

The Perfect Insect.

Who does not admire the extraordinary splendour, the vivacity, the prodigious variety of colours of these brilliant inhabitants of the air? Some amateurs have devoted to the purchase of certain butterflies large sums of money. " Diamonds,'' says Reaumur on the subject, " have perhaps beauties no more real than those of a butterfly's wings; but they have a beauty which is more acknowledged by the world in general, and which is more recognised in commerce."

Fig. 133. — Different forms of the scales of Butterflies, after Reaumur.

The essential character of butterflies and moths makes them very easily recognisable among all other insects. All have four wings, which are covered with scales, that communicate to them the brilliant colours with which they are decorated. It is these scales which adhere to the fingers when we seize one of these charming creatures.

For a long time this dust was thought to be formed of very small 1;feathers, but Reaumur showed that it is composed of little scales. I Their form varies singularly, as we may see in Fig. 133, borrowed (i'from the Memoirs of Reaumur,'"' which represents the different forms J, jof the scales which cover the wings of Lepidoptera. M. Bernard

Tome i. j planche 7, Figs. I a 23.

Fig. 133. — Different forms of the scales of Butterflies, after Reaumur.

Deschamps has closely studied them. According to this naturalist, they are composed of three membranes, or plates, superposed one on the other, of which the first is covered with granulations of a rounded form, which give to these scales their splendid and varied colours; the second plate is covered with silk, forming sometimes curious designs; the third plate, viz., that which is applied to the membrane of the wing, has the peculiar property of reflecting colours the most brilliant and the most varied, although the surface of the scales visible to the eye is often dull and colourless.

"Supposing," says M. Bernard Deschamps, "that a painter was possessed of colours rich enough to represent on canvas with all their splendour, gold, silver, the opal, the ruby, the sapphire, the emerald, and the other precious stones which the East produces, that with these colours he formed all the shades which could result from their

combination, one might affirm without the chance of contradiction, that he would have none of these colours and of their various shades,

Fig. 134- -Portion of the wing of a Moth {Satutnia pavonia major i, magnified. whatever might be the number, which could not be discovered by the microscope on part of the scales of the Lepidoptera, which Nature has been pleased to conceal from our gaze."

Each of these scales adheres to the membrane of the wing by a small tube, which is solidly fixed to it. Reaumur has called our attention to the admirable arrangement of these scales, which are disposed like those of fish, that is to say, in such a manner that those of a row shall partially overlap those in the following one.

In Fig. 134, representing a portion of the wing of the Satuniia

pavofiia major^ magnified, which we borrow from Reaumur's Memoir, the scales are arranged in rows; isolated scales, and the points

wheresented. other scales were fixed before they were taken ofi", are repre-

The membranous frame which supports the coloured scales of butterflies and moths is well worth a moment's consideration. It consists of two membranes intimately united by their interior surfaces,

LEPIDOPTERA. iGj

and divided into many distinct parts by horny, fistulous threads, more or less ramified, which seem intended to support the two membranes mentioned above, and which branch out from the base to the edge of the wing. Their number, counting from the exterior edge, is not always the same in the upper and lower wings. It varies from eight to twelve. With its large and light wings, the butterfly can fly for a long tim.e. But this flight is not in the least regular; it is not made in a straight line. When the insect has to go some distance, it flies alternately up and down. The line it takes is composed of an infinity of zig-zags, going up and down, and from right to left. This irregularity of flight saves the little insect from falling a prey to birds. " I saw one day with pleasure," says Reaumur, " a sparrow which pursued in the air a butterfly for nearly ten minutes without being able to catch it. The flight of the bird was nevertheless considerably more rapid than that of the butterfly, but the butterfly was always higher or lower than the place to which the bird flew, and where it thought it would catch it."

But let us leave the wings to pass on to the other parts of the butterfly. These other parts are the thorax or chest, the body or abdo7nen^ and the head. The thorax is solidly put together, so as to bear the movements of the wings and legs. These latter are composed, as in other insects, of five parts: the coxa, the trochanter, the thigh, the shank, and the tarsus. Many butterflies have all their six legs of equal length. In

Fig. 135 —Leg of Butterfly nrmed with hooks. Fig. 136.— Leg not suitable for waiking.

' others, the two fore legs are very small, and are not suited for walking. In others, again, they are rudimentary, being deprived of hooks, very hairy, and applied on to the front of the breast.

This difference of structure may be seen in Figs. i35 ^"^ ^.S^* one of which represents, after Reaumur, a leg unsuited for walkmg, very hairy, and terminated in a sort of brush resembling the tail on a tippet; and the other a leg fiirnished with hooks.

Fig. 135 —Leg of Butterfly nrmed with hooks. Fig. 136.— Leg not suitable for waiking.

l6S THE INSECT WORLD.

The abdomen has the form of an elongated, or — in the majority of species — an ahnost cylindrical oval. It is composed of five segments, each formed of an upper and a lower ring, joined together by a membrane. The first are larger than the others, and generally overlap the edges, which gives to this part of the body the power of dilating considerably. We must dwell longer on the head. It is generally rounded, compressed in front, longer than it is broad, and furnished with fine or scaly hairs. The important organs of which this part is the seat are the eyes, the antennae, the palpi, and the proboscis or trunk.

The eyes are more or less spherical, surrounded by hairs, and composed of innumerable facettes. Colours are seen on these as various as those of the rainbow. But the colour which serves as a base to all, is black in some, grey in others; then again there are different gold or bronze colours of the greatest splendour, inclining sometimes to red, sometimes to yellow, sometimes to green. On the compound eye of a butterfly as many as 17,325 facettes have been counted. Simple eyes, or stemmata, are moreover observed in certain species, and are generally more or less hidden by scales.

The antennae are situated near the upper rim or border of each eye. Reaumur has pointed out six principal shapes. One terminates in a little knob^ and belongs to the butterflies. The others are variously shaped, and belong to the moths. Some are prismatic, or like beading. And lastly, others are shaped like feathers. We represent, in Fig. 137, the different forms of the antennae, which Reaumur collected together in plates 8 and 9 of his fifth Memoir.

The palpi are four in number, two maxillary and two labial. The first are generally excessively small; one can only ascertain their existence by the aid of a strong magnifying glass: the second are in general very apparent, straight, cylindrical, covered with scales, and formed of three joints, of which the last is often very small and sometimes very pointed. They also sometimes bristle with stiff or silky hairs. The trunk is placed exactly between the two eyes. As long as the butterfly does not want to take nourishment, the trunk remains rolled in a spiral. Some are so short, that they scarcely make one turn and a half or two turns; some larger-sized make three turns and a half or four turns; lastly, some very long are curled as many as eight or ten times.

'I'his is how the butterfly makes use of its trunk: when fluttering

" Sur les j)ailies exteiieuies cles papilions," tome i., p. 197.

LEPIDOPTERA.

around a flower, it will very soon settle on or quite close to it. The trunk is then brought forward entirely or almost entirely unrolled; very soon afterwards it is almost straightened, then directed downwards, and plunged into the flower. Sometimes the insect draws it out a moment after, curves it, twists it a little, and sometimes even

Fig- 137. — Antennae of Lepidoptera.

curls it partially up. Immediately it straightens it again, to plunge it a second time into the same flower. It repeats the same manoeuvre seven or eight times, and then flies on to another flower.

This tmnk. of which the butterfly makes such good use, is composed of two filaments more or less long, horny, concave in their interior surfaces, and fastened together by their edges. When cut

63*

transversely, one sees, according to Reaumur,* that the interior is composed of three small rings. Consequently, there are three canals in the trunk: one central, the other two lateral (Fig. 138). Are all

these three used to conduct the juice of flowers into the butterfly's body? Reaumur has made some very interesting observations on this subject, by observing a moth which was sucking a lump of sugar whilst its portrait was being taken.

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