gles, when the spider carries it off to some nook, there to devour it.

106. One of the most common spider-nets is like the one shown in Fig. 73. If the place selected is in the opening of a window or similar place, the spider first runs a few threads as a sort of framework, to which are to be afterward attached the radiating threads, that is, those which run from the centre of the net to the sides. Having arranged these so near together that the spider can easily reach from one radiating thread to the other, the creature commences at the centre of the net, and runs a thread from one radiating thread to the other in a rapidly-unwinding spiral till it reaches the outer edge of the net. This is to form a staging, and also the better to hold the radiating threads in place. It then commences at the outside, and going back over its last course carefully constructs the permanent mesh; and, as it comes to each radiating thread, it will be seen to attach to it the thread it is now making, by simply pressing the spinnerets against it. As it goes around again and again, continually lessening the circle, it gathers up the thread which was first laid as a staging, and, tolling it up in little balls, drops it to the ground. This habit has led to the impression that the spider eats its web. The circular threads are glutinous, while the radiating threads are smooth, and this can be proved by throwing dust through the net, when the cross-threads will catch and hold the dust, while the radiating threads will remain clean. The actual centre of the net is not the geometrical or true centre, but a little above it.

It may be observed, too, that the net does not stand vertical, but leans a little, and the spider having completed the net takes a position in the actual centre of the net, head downward and on the inclining side of the net. With its legs outstretched, and resting on the radiating lines, it can feel the slightest jar or agitation made by a struggling insect. The spider being above the true centre of the net and on the inclining side, if the fly has become entangled below the centre, it can instantly drop to the desired point suspended by the ever-ready thread which it makes, and, swinging to the net, it almost instantly catches the fly.

The pupils would do well to watch the spiders while they are constructing their nets, and to observe and describe, or sketch in outline, the different kinds of nets they find and the kinds of spiders which construct them.

107. Besides the nets made by spiders to ensnare insects, some species have the power of running out a long thread which answers the purpose of a balloon in raising them from the ground and carrying them floating a long distance in the air. In constructing this buoyant means of transportation, the spider does it at peculiar times of the day, and in peculiar positions. Selecting some place where the heated air is rising from the ground or from the side of a fence, it turns up its abdomen and allows the rising current of air to carry upward the thread which is being made, and, when this thread is of sufficient length for its buoyancy to overcome the weight of the spider, it floats away with the spider hanging below.

The following represents the young spider in the atti

tude of throwing out its thread for the purpose of sailing in the air.

Voyagers often meet with these spiders in myriads as the wind sweeps them from the land.

FIG. 111.-YOUNG SPIDER GREATLY ENLARGED, SHOWING ITS ATTITUDE IN THROWING OUT THE THREAD, PREVIOUS TO RISING FROM THE GROUND. (Copied from a Figure by J. H. Emerton.)

108. The spider also constructs cases to hold her eggs, and lines them warmly with the finest web. These nests vary

greatly in appearance. A very common variety, somewhat

oval in shape, may be found suspended in barns and sheds. The pupils should collect and open these cases or nests, and they will be found to contain little eggs, sometimes rolling out like beads into the hand, or, the eggs having hatched, hundreds of little spiders will appear moving within the nest.

Nests, or, more properly speaking, egg-cases of different kinds, may be collected under stones and logs, and wherever spiders' nests occur. The little spiders hatching from the egg

will grow to twice their size in the nest, without apparent food, and it becomes evident that, in some cases, they must eat each other, as Prof. Wilder has observed within some of the egg-cases a far less number of spiders than there were eggs in the nest at the outset. These nests may be kept in boxes, and the eggs will hatch in due time.

FIG. 112.-SPIDERS' NESTS OF DIFFERENT KINDS CONTA NING EGGS.-A and C are common nests in sheds and barns; B was found under a board in the field, the part containing the eggs stands upon a stalk.

109. The young spider comes from the egg resembling in form the parent spider, except that the legs are much shorter in proportion to his relative size, and the palpi appear so large that they look like another pair of legs, as they then are in fact, but they afterward become modified to feelers.

y

m

FIG. 113.-ENLARGED FIGURE OF A YOUNG SPIDER JUST FROM THE EGG, WITH THE FIRST MOULT, m, adhering to the Hinder Part of the Body; y, the Natural Size of the Spider; 1, extremity of a Leg bighly magnified, showing an Outer Skin which has not been shed.

As the young spider grows, it sheds its skin at short intervals of time. If the pupils will examine the young spider soon after it is hatched from the egg, they will find attached to the hinder part of the body the skin which has just been shed. This curious process of shedding the skin, or moulting, occurs at intervals, till the spider has reached adult size.

FIG. 114.-THE CAST-OFF SKIN OF AN ADULT SPIDER.

110. The cast-off skins of spiders are very common in their webs, and, if the pupils examine any barn-window which is covered with spider's webs, they will be sure to find some of these cast-off skins, like the one represented in Fig.

114.

The mother-spider, generally so timid, overcomes her fear during the time she has the care of her eggs, and with many spiders the egg-cases are directly cared for by the mother, she oftentimes carrying them about with her or holding on to them and showing the greatest solicitude for their safety. Let the pupils try to separate the egg-case from the mother-spider, and they will then learn how courageous the spider is at this time, and how persistently she remains by her eggs. Some species of spiders carry their young on their backs, and move about with them.