"If the weather was cold or damp, she retired to her tunnel; but if the jar in which she lived was set where the sun

spider.

could shine upon it, she soon re

appeared and allowed the cocoon to bask in the sunlight. If the jar was placed near a stove that had a fire in it, the cocoon was put on the side next the source of warmth; if the jar was turned around, she lost no time in moving the cocoon to the warmer side. Two months after the eggs were laid the

young spiders made their appearance and immediately perched upon their mother, many on her back, some on her head, and even on her legs. She carried them about with her and fed them, and until they were older they never left their mother for a moment."

146. Insects. So much space has already been devoted to an account of the elaborate nest-making and domestic habits of the bees, ants, and termites (see Chapter IX), that we need in this place merely refer to that account. It is among these social insects that the most interesting and highly specialized habits connected with the care of the young and the building of homes are found.

Many insects make for themselves simple burrows or nests in the ground or in wood. The young or larvæ of certain moths burrow about in the soft inside tissue of leaves, and the whole life of the moth except its short adult stage is passed inside the leaf. These larvæ are called leaf

miners. The larvæ of some moths and of many hymenopterous insects live in galls on live plants. These galls are simply abnormal growths of plant tissue, and are caused by the irritating effect on the tissue of the larvæ which hatch from eggs that have been thrust into the soft plant substance by the female insects. In the familiar galls on the golden-rod live the larvæ of a small moth, and in the various kinds of oak galls live the young of the numerous species of Cynipida, the hymenopterous gall insects. The tiny larvæ of some of the midges live in small galls on various plants. To this last group of gall-making insects belongs the dreaded Hessian fly, the most destructive insect pest of wheat.

Among the bees and wasps only a few species, comparatively, are communal or live in communities. But nearly all the wasps and bees, whether social or solitary in habit, build nests for their young and provide the young with food, either by storing it in the nest or by hunting for it and bringing it to the nest as long as the young are in the larval condition. The "mud-daubers" or thread-waisted wasps make nests of mud attached to the lower surface of flat stones, to the ceiling of buildings, or in other out-ofthe-way and safe places. These nests usually have the form of several tubes an inch or so long placed side by side. In each of the tubes or cells an egg is laid, and with it a spider which has been stung so as to be paralyzed but not killed. When the young wasp hatches from the egg as a grub or larva, it feeds on the unfortunate spider. Others of the solitary wasps make nests in the ground or in wood, and all of them provision their nests with some particular kind of insect or spider. Some use only caterpillars, some plant-lice, and some grasshoppers. Similarly the solitary bees make nests in the ground as do the mining-bees, or in wood as do the carpenter-bees, or by cutting and fastening together leaves, as do the leaf-cutting bees. The bees provision their nests, not with paralyzed

insects, but with masses of pollen or pollen mixed with nectar.

147. The vertebrates. It is among the vertebrates, especially in the higher groups, the birds and mammals, that we find the care of the young most perfectly undertaken and most widespread.

Among the fishes, the lowest of the vertebrates, most species content themselves with the laying of many eggs in a situation best suited for their safe hatching. But some species show interesting domestic habits. The female catfish swims about with her brood, much as a hen moves about with her chickens. Some of the larger ocean catfish of the tropics receive the eggs or the young within the mouth for safety in time of danger. Certain sunfishes care for their young, keeping them together in still places in the brook. They also make some traces of a nest, which the male defends. The male salmon scoops out gravel to make a shallow nest, in which the female deposits her eggs. The male then covers the eggs. The males of the species of pipe-fish and sea-horses receive the eggs of the female into a groove or sac between the folds of skin on the lower part of the tail. Here they are kept until the little fishes are large enough to swim about for themselves. The brave little sticklebacks build tiny nests about an inch and a half or two inches in diameter, with a small opening at the top. The eggs are laid in this nest, and the young fish remain in it some time after hatching. The male parent jealously guards the nest, and fights bravely with would-be intruders.

The batrachians and reptiles rarely show any care for their young. The eggs of most batrachians are laid in the water and left by the female. The males of the Surinam toad receive the eggs in pits of the spongy skin of the back, where they remain until the young hatch. The eggs of snakes are laid under logs or buried in the sand, and no further attention is given them by the parents.

Among the birds, on the other hand, nest-building and

care of the young are the rule, and a high degree of development in these habits is reached. All of us are familiar with many different kinds of nests, from the few twigs loosely put together by the mourning-dove to the firm, closely knit, wool or feather lined nest of the hummingbird (Fig. 159), and the basket-like hanging nest of the

oriole (Fig. 161). Not all birds make nests. On the rocky islets of the northern oceans, where thousands of puffins and auks and other maritime birds gather to breed, the eggs are laid on the bare rock. At the other extreme is the tailor bird of India, which sews together leaves by means of fibrous strips plucked from a growing plant to