In all these wings the pupil will observe a net-work of lines, which stiffen the wing and support the delicate membrane constituting the wing, just as the frame of a kite stiffens and supports the paper that is stretched upon it. These lines are called veins, or nervures. To study the vena

FIG. 60.-AN IN- FIG. 61.-AN INSECT WITH FIG. 62.-AN INSECT WITH FOUR WINGS. TWO WINGS.

SECT WITHOUT

WINGS.

tion of the wings, is to study the way in which these veins are arranged. It would be well for the pupils to stick upon a card a number of different kinds of wings, such as those of the grasshoppers, beetles, flies, wasps, and label them accordingly.

58. In many insects the forward and hinder pair of wings are of the same nature, as in the butterflies, moths, bees, wasps, and dragon-flies. In other insects, however, the forward-wings differ in character from the hind-wings. Thus, in the grasshopper the forward pair of wings are more dense in structure than the hind-wings, though the little veins may be seen closely crowded together. They differ as well in form. (See Fig. 64.)

In other insects, as in the squash-bug, the front-wings

have the half nearer the body dense and stiff, while the remaining portion of the wing is very thin, or membranous.

In the beetles the front wings are hard throughout, and in most of them are bent and moulded to the shape of the body, and, when closed, form a tight cover over the hindwings.

The forward-wings of a beetle are so unlike ordinary wings, that they are not called wings, but are known as elytra, a single one being called an elytron.

59. When insects are at rest, they generally bring their wings into a position different from that taken by them in flight. In certain dragon-flies, however, the wings when

Butterfly at rest with wings

meeting over the back.

Moth at rest with the wings sloping on the sides of the body.

FIG. 63.-INSECTS AT REST.

at rest assume the same position as they do when flying. In the butterfly the wings are brought together over the back when at rest, while the moths with few exceptions rest them sloping over the abdomen, the front-wings covering the hinder-wings.

In the grasshopper, the front-wings are long and narrow, while the hind-wings are large and broad. When the grasshopper is at rest, the hind-wings are folded together precisely like a fan, and, when closed, rest against the sides of the abdomen, the long, narrow front-wings closing down upon them, and covering them.

60. Let the pupils prepare a grasshopper, with the wings spread as in the act of flying. A specimen which is dry may be moistened by wrapping it up in a piece of wet cloth, and letting it remain a day or two.

Hinder-wing.

it

Having softened the joints of the insect in this way, may then be pinned to a piece of cork, or a pin-cushion, and, the wings having been stretched, they may be pinned in this position, using triangular bits of card through which the pins are passed to hold the wings in place, as represented in Fig. 64, which shows a grasshopper with the wings on

one side of the body pinned in the way described. When the insect becomes perfectly dry the wings will remain in the position in which they were pinned.

A common beetle should be prepared in the same way.

In the beetle the front-wings are very hard and are closed tightly over the hind-wings. With a pin, or the blade of a knife, the upper or front wings may be opened, and beneath these will be seen the hind-wings, not folded like a fan as in the grasshopper, but folded or bent in the middle, as the arm is bent at the elbow.

FIG. 65.-A BEETLE WITH THE ELYTRON AND HIND-WING OF THE RIGHT SIDE OPEN, AND THE ELYTRON OF THE LEFT SIDE OPEN WITH THE LEFT HIND-WING FOLDED IN ITS NATURAL POSITION WHEN CLOSED.

61. The abdomen has no wings or legs, but is plainly marked with lines running across the abdomen transversely.

FIG. 65.-ABDOMEN OF A DRAGON-FLY, SHOWING RINGS OR SEGMENTS.

These lines show the separation of the abdomen into rings, or segments. In insects with lengthened and slender abdomens the segments are long, and the abdomen, when bent or curved, bends at these joints, as shown in Fig. 67.

FIG. 67.-INSECT WITH A LONG, SLENDER ABDOMEN.

If the pupil can handle these parts delicately enough, he may be able to separate the abdomen at these joints, into a series of rings, or segments, and glue them on a card, marked "Rings or segments of the abdomen." In the grasshoppers the segments show very plainly. On the hinder part of the abdomen there are various appendages, sometimes so short as to be scarcely perceptible, sometimes long, and thread-like, as in the May-fly (Fig. 98); again, in the shape of a sharp sting, as in the hornet. In the cricket, they are quite long and conspicuous. These appendages vary greatly in different insects.