such a protection unnecessary. The dense rugged texture with which V. germanica keeps off the drip and the falling earth from her nursery when she builds under ground, is changed for a lighter, freer style of construction when she hangs her nest from a rafter. And so it is, too, with V. vulgaris.

The assurance of a coming dry summer is communicated to wasps by signs which we take at second hand from them. I am told, by a gamekeeper who has spent his life in a land of brooks, that the height at which the wasps make their nests above the water is a rough index of the amount of rain that is to be expected during the summer. In a wet season they choose the top of the bank; in a dry year they extend their range nearer to the water-level. When these indications, whatever they may be, induce V. sylvestris to build in the hole which she has scooped in the side of a hedge-bank instead of in her more usual position, she makes a much slighter case than when she has to provide against wind and rain. But the structure is still characteristically that of the species in all these cases; and the nest, in whatever situation it may be placed, and however it may be modified to suit the requirements of its unusual position, bears distinctive marks of the workmanship of the particular kind of wasp. The architecture is as typical of the species as the markings of the insect, and the instinctive habit of building in one particular way is as inseparable from the individual as its own organs. Though an occasional alteration of the seasons may give rise to corresponding changes in the place or mode of construction, yet these changes, do not go so far as essentially to

alter the style of the nest. A permanent alteration of the climate, such as the insects could not adequately temper for themselves, would probably destroy the local species, and cause the naturalization of others from foreign countries. But though a change of seasons and climate might bring the Chartergus, for instance, here with her card-board nest, there is no reason to think that any such climatic changes would induce the British wasps to build card houses.

One thing more British wasps' nests have in common, namely, the end of all their labour, the wreck and ruin of their wonderful fabric. Where no accident has interfered with its growth, or brought it to an untimely end, the limits to the size of a nest are prescribed by physical and physiological laws. The latter class, to which we shall return farther on, are probably the most important, but certain physical considerations lead to the conclusion that a paper structure of this nature cannot grow very large. In the species which use a more textile material, the constantly increasing deviation of the marginal cells from the normal vertical direction has probably something to do with limiting the lateral growth of the comb. And where the more friable nature of the materials excludes this particular limitation, compelling the cells to be built straight and parallel throughout, in this very circumstance we have another not less important influence at work, restricting to a few inches the diameter of a comb which could have any reasonable chance of holding together. And so, too, with regard to the number

of tiers of comb; the nature of the material prescribes very narrow limits within which the number of heavy wet combs, hanging from one another, can be safely multiplied; even were there wasps enough to extend the fabric, or did the season allow them to prolong their operations, indefinitely.

Then, as to the duration. The history of even the most long-lived swarm of wasps extends only over a few weeks. The end comes very speedily as well as surely, whatever the cause; and the story of the decay of the nest, whose growth we have traced, may be told in a few lines. Thus :-No additions are made to the structure, the repairs are neglected, the loose ends are not neatly cut off and fastened down. A few idle wasps hang about; but the nest seems almost deserted. Perhaps a shake of the hedge will bring out a few fussy wasps for a minute, or a sunny afternoon will develop signs of life in the remains of the swarm, yet their strength is gone. A cold night or two, a few damp cold days, and all is over. Now, the collector may take his prize safely; and he must be quick about it, for, if he delays, the rain and wind will soon destroy whatever of this curious structure the moths, and wood-lice, and earwigs have spared. These, and other insects abhorred of all naturalists who have collections, are now its occupants.

Lucifugis congesta cubilia blattis.*

The little creatures who made it and held it against all comers have succumbed to cold, and disease, and old age, like other brave soldiers. They have skulked

*Virg. 'Georg.' IV, 244.

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off to die, like old cats, away from home; and the most unlikely place to find a live wasp in is an old wasps' nest.

We have now, to complete this part of the subject, to inquire how the nests of the several species differ respectively from the common type, and what are the marks by which we can identify them. In the earliest stage of its existence the nest, as a rule, displays nothing very characteristic of the particular species. After the examination of some dozens of the embryo nests of the common British wasps, I must confess that I should have great difficulty in referring each of these to its proper owner. As they grow larger the difficulty vanishes, the form of the nest, the details of its structure and the materials of which it is composed, all, as we shall see, coming to our assistance in drawing the distinction.

The hornet (Plates VI. and VII.) forms her nest of a brittle, yellow, thick paper, composed of fragments of rotten wood, often mixed with sand, or with any thing that can be glued up into a mass. Hornets' nests are not generally as populous as wasps' nests, and the swarm is more economical of its labour. They do not always care to cover the comb with a distinct case of paper when the cavity in which the nest is built might seem to render any additional protection unnecessary. However, when the nest is built in an open space, as in a roof, the case is quite as thick in proportion to the size of the nest as any of the smaller wasps would have made it.

The outer cases of wasps' nests are made on one of two general plans, which may be called the cellular or laminar respectively. Hornets' nests, like those of V. vulgaris and V. germanica, are made on the former plan. A transverse section shows the entire thickness to be built up of segments of circles applied irregularly one over the other, something in the way that semicircular tiles are built into ornamental walls for suburban villa gardens. Hunter,* says: "A section of the outer coat from top to bottom would almost give the idea of its being built with the wafers made by the confectioners." By this mode of construction a number of tunnels or, more correctly, long culs de sac are made, generally running parallel to the vertical axis of the nest. The outside of the nest is uneven with the openings of these tunnels, which are all directed downwards; but the inside is smooth, with a clear way all round between the case and the combs. The nest is most commonly of an oval form, with the long axis vertical.

Everything, of course, is on a very large scale, as compared with the nests of the smaller species. Taking the measures from a large specimen in my cabinet, which had been built in a cottage roof in Gloucestershire, these quite eclipse the proportions of the ordinary wasps' nests. The transverse diameter is fifteen inches, and the vertical measure is as much as nineteen, although full three inches or more have been taken off the bottom of the nest. The span of some of the longitudinal cells or tunnels is six inches, and their average width is not less than

* Hunter Posthumous Works,' by Owen, Vol. I, p. 74.