manner trace the art of mining to a rabbit-burrow, or a fox-earth, or, to come to our immediate subject, to the mined holes of the bank-swallow, or sand-martin, (Hirundo riparia). These constructions could not fail to strike the most indifferent observer the first time they were seen. Yet, simple as such holes appear, they have given rise, as we shall afterwards see, to several very singular misconceptions, not only among the vulgar, but among naturalists of distinguished reputation*.

We cannot well conceive how it happened that White of Selborne, usually so accurate in his facts, should have committed so many mistakes respecting the bank-swallow. These mistakes are the more unfortunate, as they have been implicitly copied by almost every succeeding writer. "Perseverance," says White, "will accomplish anything; though at first one would be disinclined to believe that this weak bird, with her soft and tender bill and claws, should ever be able to bore the stubborn sand-bank, without entirely disabling herself; yet with these feeble instruments have I seen a pair of them make great dispatch; and could remark how much they had scooped that day, by the fresh sand which ran down the bank, and was of a different colour from that which lay loose and bleached in the sunt."

Whoever, on the contrary, looks at the bill and claws of the bird, cannot fail to be convinced, that so far from being "soft and tender" they are more than commonly hard and sharp, and admirably adapted for digging. The bill, we admit, is small, but its very shortness adds to its strength, as it suddenly tapers to a point like a sailor's marlin-spike, or rather like the points of a pair of fine compasses

See Pliny's account of the swallow embankment on the Nile, in our chapter upon "Mason Birds."

+ Nat. Hist. Selborne, i. 299, ed. 1825.

this bird (chuck-will's-widow) has on each foot; but, reader, this remains one of the many desiderata in ornithology, and I fear, with me at least, it will continue so Yet, while we do not pretend to be able to decide the question, we think Wilson's account the most plausible. The recorded fact, which he actually observed, cannot surely be overturned by the general remark that it is preposterous to suppose these birds furnished with a peculiar instrument which would be no less useful to all birds. In answer to this, we are entitled, by parity of reasoning, to say that it is equally preposterous, according to the other explanation, to suppose the serrated claw confined to the night-jars, as other birds which feed upon chafers, the kestril (Falco tinnunculus, RAY†), for example, are not furnished with any thing of the kind. After all, the serratures may be intended for none of these purposes, but for enabling the bird to hold more firmly when it alights

are more irregular in form; but this seems to depend more on the sand crumbling away than upon any deficiency in the original workmanship. The bird, in fact, always uses its own body to determine the proportions of the gallery-the part from the thigh to the head forming the radius of the circle. It does not trace this out as we would do, by fixing a point for the centre around which to draw the circumference. On the contrary, it perches on the circumference with its claws, and works with its bill from the centre outwards; and hence it is that in the numerous excavations recently commenced, which we have examined, we have uniformly found the termination funnel-shaped-the centre being always much more scooped out than the circumference. The bird consequently assumes all positions while at work in the interior, hanging from the roof of the gallery with its back downwards as often as standing on the floor. We have more than once indeed seen a bankswallow wheeling slowly round in this manner on the face of a sand-bank, when it was just breaking ground to begin its gallery*.

This manner of working, however, from the circumference to the centre, unavoidably leads to irregularities in the direction, which would not so readily occur by reversing the procedure; for though the radius formed by a part of the bird's body is subject to little variation, yet the little that does occur from the extension or contraction of the neck, must tend to throw it out of the right line. Accordingly, all the galleries are found to be more or less tortuous to their termination, which is at the depth of from two to three feet, where a bed of loose hay and a few of the smaller breast feathers of geese, ducks, or fowls is spread with little art for the reception of the eggs t. It may not be unimportant to remark also, that it

and is certainly the organ which apprizes the bird of any rumpling or clotting of the plumelets; and when such derangement is perceived, a pause is instantly made till the part is properly adjusted. We have observed a young green-bird (Fringilla chloris) preening its wings as they became dry after washing; and we could distinctly perceive the tongue employed both for ascertaining the parts that were rumpled, and for licking them straight when merely passing them through the bill was found to be insufficient *.

That this, though it may be considered a novel statement, is notwithstanding a correct one, may be corroborated analogically, by referring to the similar manner in which other animals clean themselves. Quadrupeds have no glands similar to those in birds erroneously conjectured to furnish a dressing oil; yet the greater number of quadrupeds have their fur smooth and even glossy, simply from licking it, as our young green-bird was seen to do its feathers. The cattle in our pastures may in this way be seen passing their moist tongues over their hair; and the elephants in our menageries may be observed using the moist extremity of their proboscis to clean their rough hairless skin. Even among the insects, whose habits and economy are so very different, we have, at least in one curious instance, remarked the process of cleaning performed on the same principle by a moistened instrument. Our readers may be pleased, by way of illustration, to see the original account of this instrument observed in the grub of the glow-worm (Lampyris noctiluca).

"In an excursion for the purposes of natural history to the woods of Dartford, in Kent, the 14th of last March, I found an insect, which I had not

* J. R.

hitherto met with, creeping upon the mossy trunk of an oak, which, besides, was entwined with honeysuckle, and near the bottom a fern plant was rooted among the decaying bark. This insect much resembled the female glow-worm in external appearance, but it was considerably longer, and the colours were different. Its head, though small, was formed like those of the grubs of predaceous beetles, whence I conjectured it might belong to some of their numerous families; but lest I might be deceived in this, and that after all it might be a vegetable feeder, I put some of the oak bark, moss, fern, and honeysuckle, along with it into a collecting box. Into the same box I afterwards put several specimens of small snails, with pellucid shells, which I found in the same locality-a circumstance which led me to the discovery of one of those facts that, after eluding direct research, are often the result of accident.

"It was not till next day that I looked into the box, when I perceived that none of the vegetable substances had been touched, for the snails had glued themselves to the lid, according to their usual custom when put into a dry place; and though the little stranger was sufficiently lively, and walked about in all directions, nothing within reach appeared to suit its taste. After watching it for some time, my attention was drawn to some very singular movements which it made with its tail, and which the reader will understand better if he has observed how the common earwig, or the insect popularly called the devil's coach-horse (Goërius olens, STEPHENS), bends up its tail over its back, somewhat in the manner of a spaniel when it trips along well pleased before its master. The forked tail of the earwig, however, as well as that of the Goërius, is said to be used in assisting to unfold its long and closely-folded wings,