several pairs of Grakles taking up their abode there, like humble vassals around the castle of their chief,-laying, hatching their young, and living together in mutual harmony. I have found no less than four of these nests clustered round the sides of the former, and a fifth fixed on the nearest branch of the adjoining tree, as if the proprietor of this last, unable to find an unoccupied corner on the premises, had been anxious to share, as much as possible, the company and protection of this generous bird." In another place, the same writer remarks that the curious allies "mutually watch and protect each other's property from depredators."

These Grakles exist in great numbers, and sweep over the land in vast flocks, like our own starlings, their wings sounding like the blast of a tempest as they rise from the ground, and their bodies darkening the air. "A few miles from the banks of the Roanoke, on the 20th of January, I met with one of these prodigious armies of Grakles. They rose from the surrounding fields with a noise like thunder, and, descending on the length of road before me, covered it and all the fences completely with black; and when they again rose, and, after a few evolutions, descended on the skirts of the high timbered woods, they produced a most singular and striking effect, the whole trees, for a considerable extent, seeming as if hung in mourning; their notes and screaming the meanwhile resembling the distant sound of a great cataract, but in more musical cadence, swelling and dying away on the ear, according to the fluctuations of the breeze."

It is evident that such vast multitudes of birds cannot all have been nurtured in the interstices of osprey nests. Indeed, the generality of the birds build in tall trees, usually associating together, so that fifteen or twenty nests are made in the same tree. The nests are well and carefully made of mud, roots, and grasses, about four inches in depth, and warmly lined with horsehair and very fine grasses. The fact that the bird possesses this capability of nest-building, gives more interest to the occasional habit of sharing its home with the osprey-a privilege of which it seems to avail itself whenever an osprey's nest is within reach.

The colour of this bird appears at a little distance to be black, but is in reality a very deep purple, changing in different lights

to green, violet, and copper, and having a glossy sheen like that

of satin.

OUR little friend the SPARROW (Passer domesticus) is occasionally a parasite, following to some extent the custom of the purple grakle, though it does not select a bird of prey for its companion.

On the Continent, the common stork builds largely, and in several countries is protected by general consent, the slaughter of a stork, or the destruction of its nest and eggs, being visited with a heavy fine. In consequence of this immunity, the stork is very tame, building upon houses as freely as does the martin, and being considered as a bringer of good luck when it does so.

Any disused chimney is sure to have a stork's nest upon the top, and so is a pillar, or any ruin. The nest of the stork bears a general resemblance to that of the osprey, and, with the exception of the sea-weed, is made of similar materials. It is of huge dimensions, and chiefly consists of sticks and reeds, heaped together without much arrangement, and having on the top a slight depression, in which the eggs are laid. As is the case with the osprey nest, considerable interstices are left between the sticks, and in these spots the Sparrow loves to place its nest. Mr. F. Keyl has told me that he has repeatedly seen the storks and Sparrows thus living in amity together, the stork appearing to extend to a weaker bird that protection which it receives from mankind.

WE now pass to the Parasitic Insects. As this work is intended to describe dwellings which are in some way formed by the creatures, it is necessary to exclude all the parasite insects that may exist upon the animal, and make no habitation, such as the ticks, as well as those which are merely parasitic within the animal, such as the various entozoa.

Of Parasitic Insects, the greater number belong to that group of hymenoptera which is called Ichneumonidæ, and which embraces a number of species equal to all the other groups of the same order. Being desirous of producing, as far as possible, those examples of insects which have not been figured, I have selected for illustration several specimens which are now in the

British Museum, one or two of which have only been recently placed in that collection.

THE best known of all the Ichneumonidæ is that tiny creature called Microgaster glomeratus, of which a casual mention has already been made in page 270.

A group of these insects and their cells is now before me, and will be briefly described.

The insects themselves much resemble in general form the Burnet ichneumon which is mentioned in pp. 270, 273, but are smaller, blacker, and not nearly so beautiful, although their wings gleam with an iridescence nearly as brilliant. Small as it is, this tiny insect is extremely valuable to us, and to the gardener is beyond all value, though, as a general rule, the gardener knows nothing about it. Were it not for this ichneumon, we should scarcely have a cabbage or a cauliflower in the garden; for the noisome cabbage caterpillars would destroy every leaf of

the present plant, and nip the growth of every bud which gave promise for the future.

Every one knows the peculiarly-offensive caterpillars which eat the cabbages, and which are the offspring of the common large white butterfly. In the spring, the butterflies may be seen flitting about the gardens, settling on the cabbages for a few moments, and then flying off again. They look very pretty, harmless creatures, but, in fact, they are doing all the harm that lies in their power. Forty or fifty eggs are thus laid on a plant, and if only one quarter of the number are hatched, they are quite capable of eating every leaf. In process of time, they burst from the egg-shell, and commence their business of eating, which is carried on without cessation throughout the whole time of the larval existence, with a few short intervals, while they change their skins.

When they are full grown, they crawl away from the plant to some retired spot, and there suspend themselves, preparatory to changing into the pupal condition. A few of them succeed in this task, but the greater number never achieve the feat, having been the unwilling nourishers of the ichneumon flies. Just before the larva is about to pass into the pupal state, a number of whitish grubs burst from its sides, and each immediately sets to work at spinning a little yellow, oval cocoon. The walls of

the cocoon are hard and smooth, especially in the interior; but the outside is covered with loose floss-silk, which serves to bind all the cocoons together. Generally, they are very loosely connected; but a group of these little objects is now before me, where the cocoons are formed into a flattish oval mass, about the size and shape of a scarlet-runner bean, split longitudinally, and are bound so tightly together, that their shape can barely be distinguished through the enveloping threads.

As is the case with the cells of the Burnet ichneumon, each cell is furnished with a little circular door, which exactly resembles in shape and dimensions the circular pieces of paper that are punched out of the edges of postage-stamps. On the average, about sixty or seventy ichneumon flies are produced from a single cabbage caterpillar.

The groups of yellow cells are very plentiful towards the middle of summer and the beginning of autumn, and may be found on walls, palings, the trunks of trees, in outhouses, and, in

fact, in every place which affords shelter to the caterpillar. Nothing is easier than to procure the insects from the cocoons, as the yellow mass needs only to be put into a box, with a piece of gauze tied over it by way of a cover. Nearly every cocoon will produce its ichneumon, and as the little creatures are not strongjawed enough to bite through the gauze, they can all be secured.

There are many species of Microgaster; but those which have been mentioned are the most important, and make the most interesting habitations.

THE large oval cocoon was brought from New South Wales, and is evidently the produce of some lepidopterous insect, probably a moth allied to the silkworm. Upon the larva which constructed the cocoon an ichneumon has laid her eggs, and the consequence has been that the caterpillar has been unable to change into the pupal condition, but has succumbed to the parasites which infested it. These insects are not of minute dimensions, like the Microgaster, but are tolerably large, and in consequence can be but few in number. The cells are very irregular in shape, and are not rounded like those of many Ichneumonidæ, but have angular edges.

In this, and in one or two other examples which are shown in the illustration, the reader will note a peculiarity in the development of the parasite. The Microgaster larvæ emerge from the caterpillar just before it undergoes its change into the pupal condition, and effectually prevent that change by killing the creature in which they had been nurtured. But, in many instances the ichneumon larva delays its escape until the caterpillar has completed its cocoon, and in some cases waits until the change into the pupal state has been achieved. In the present example, the larva has permitted the cocoon to be made, and then killed the caterpillar, the reason of this delay being that the cocoon is very firm and strong, and affords an impregnable shelter to the parasite. The names of the Parasites are placed beneath the

cocoons.

WITHIN the same case there are several cocoons in which a similar calamity has befallen the caterpillars which made them. There is, for example, a cocoon of the OAK-EGGER MOTH (Lasiocampa quercus), the interior of which resembles that of the insect which has just been described, except that the cells of the parasite