conjecture what had made it take a fancy to so singular a helmet; but I soon perceived that it was in fact making prey of the poor snail-having, for that purpose, thrust its narrow extensile head half to the bottom of the shell, which it did not quit till it had devoured the inhabitant.

It was thus proved to me that it was not a vegetable feeder, but carnivorous; and I subsequently found, upon trial, that it would touch no animal except snails. Its head, from being extensile, is well adapted for pursuing its prey to the inmost recesses of their shells; and its mandibles, which are curved in form of a pair of calliper compasses, appear, as in the instance of the grub of the ant-lion (Myrmeleon formicarius), to be employed rather for sucking than for eating, though I was unsuccessful in satisfactorily ascertaining this point.

b

a

Head of the glow-worm grub. a, the head; b, the neck; c, the antennæ; d, the jaws.

It is more to the present subject to mention, that the grub cannot well devour one of its victims without being soiled with slime; and accordingly, after every repast, I observed that it went carefully over its head, neck, and sides, with its cleaning instrument, to free them from slime.

Though not directly connected with my immediate subject, it may be interesting to many readers to mention that the above grub, as well as those observed by Baron de Geer, distinctly proved the fallacy of the common doctrine respecting the light of the glow-worm, which goes to maintain that it is a lamp, lit up by the female, to direct the darkling flight of the male. 'Ce sont,' exclaims Dumeril, les flambeaux de l'amour-des phares-des télégraphes nocturnes-qui brillent et signalent au loin le besoin de la reproduction dans le silence et l'obscurité des nuits*. Mr. Leonard Knapp, refining upon this notion, conjectures that the peculiar conformation of the head of the

*Dictionnaire des Sciences Naturelles, xxv. 216.

male glow-worm is intended as a converging reflector of the light of the female, always beneath him on the earth.'' As we commonly,' he adds, and with advantage, place our hand over the brow, to obstruct the rays of light falling from above, which enables us to see clearer an object on the ground, so must the projecting hood of this creature converge the visual rays to a point beneath *.'

Unfortunately for this theory, the grubs—which, being in a state of infancy, are therefore incapable of propagating-exhibit a no less brilliant light than the perfect insect. De Geer says the light of the grub was paler, but in the one which I had it was not so. He also remarked the same light in the nymph state, which he describes as very lively and brilliant;' and, in this stage of existence, it is still less capable of propagating than in that of larva. 'Of what use then,' he asks, is the light displayed by the glow-worm? It must serve some purpose yet unknown. The authors who have spoken of the male glow-worms say positively that they shine in the dark as well as the females t.' These plain facts appear completely to extinguish the poetical theory. But to return to our immediate subject.

A very remarkable instrument, which recent observations seem to prove to be intended for a similar purpose to that of the caudal apparatus of the glow-worm, just described, occurs in the fern-owl, or night-jar (Caprimulgus Europaus), popularly called the goat-sucker, from an erroneous notion that it sucks goats-a thing, which the structure of its bill renders impossible as that of cats sucking the breath of infants, as is also popularly believed. The bird alluded to has the middle claw cut into serratures, like a saw or a short-toothed comb; the use of which structure seems to have been misunderstood by White of Selborne.

Foot of the European night-jar, shewing the pectinated claw.

* Journal of a Naturalist, p. 292, first edition.
† De Geer, Mem. iv. 44.

If it takes,' says he, any part of its prey with its foot, as I have the greatest reason to believe it does chafers, (Zantheumia solstitialis, LEACH, MS.,) I no longer wonder at the use of its middle toe, which is curiously furnished with a serrated claw*.' Mr. Dillon has recently controverted this opinion; his observations leading him to suppose that the serratures are employed by the bird to comb its whiskers (vibrissa). Mr. Swainson, again, a high authority on such a subject, thinks that the fact of an American group of the same birds (Caprimulgida), which have no whiskers to comb, and an Australian group, which have whiskers, but no serratures on the claws, are discordant with Mr. Dillon's opinion ‡. It frequently happens, however, that the most ingenious and apparently incontrovertible reasoning in natural history, is overturned or confirmed by facts accidentally observed. I was, I confess, disposed to think Mr. Dillon's opinion more plausible than true, and to agree with White, and the learned arguments of Mr. Swainson, till I met with some observations of the distinguished American ornithologist, Wilson, upon some of the transatlantic species. In his description of the whip-poor-will (Caprimulgus vociferus), he says, 'the inner edge of the middle claw is pectinated, and, from the circumstance of its being frequently found with small portions of down adhering to the teeth, is probably employed as a comb, to rid the plumage of its head of vermin, this being the principal and almost the only part so infested in all birds §.'

Of another species, called chuck-will's-widow (C. Carolinensis), he says, their mouths are capable of prodigious expansion, to seize with more certainty, and furnished with long hairs or bristles, serving as palisades to secure what comes between them. Reposing much during the heats of the day, they are much infested with vermin, particularly about the head, and are provided with a comb on the inner edge of the middle claw, with which they are often employed in ridding themselves of these pests, at least when in a state of captivity .' Considering the utility of such an instrument, we may wonder,

Nat. Hist. of Selborne, i. 160. Ed. Lond. 1825.

Loudon's Mag. of Nat. Hist. ii. 31.
Wilson's American Ornithology, v. 77.

Ibid. iii. 188.

Ibid. vi. 97.

perhaps, that, besides the herons (Ardea), no other birds are similarly provided for attacking those troublesome insects (Homaloptera, MACLEAY, Nirmida, LEACH, &c.), which often seriously injure the vigour and health of the animal infested, and sometimes even occasion death. On going to visit the ruins of Brougham Castle, in Cumberland, I was struck by the unusual tameness of a swallow (Hirundo rustica), which I found sitting on the parapet wall of the bridge which crosses the Emont, on the road from Penrith. Swallows are, indeed, far from being generally shy, trusting, perhaps, to their rapidity of flight should danger threaten; but this poor swallow allowed itself to be approached, without offering to escape. It seemed, in fact, instinctively courting human aid, at least I was inclined so to interpret its pitiful looks. On taking hold of it, I found the feathers swarming with an insect (Craterina Hirundinis, OLFERS) somewhat larger in size than the common house-bug (Cimex lectularius). I took the poor bird immediately to the river; and, on being freed from its tormentors, it flew off joyfully to join its companions. Had it been furnished with a comb, like the night-jars, it would not probably have needed my assistance.

It may not fall in the way of many of the readers of this paper to make personal observations on the foot-comb of the night-jar; but similar instruments, of still more ingenious construction, may be inspected, by whoever will take the trouble, in two of our most common animals-the cat and the house-fly (Musca domestica), both of which may very frequently be seen cleaning themselves with the utmost care. The chief instrument employed by the cat is her tongue; but when she wishes to trim the parts of her fur which she cannot reach with this, she moistens, with saliva, the soft spongy cushions of her feet, and therewith brushes her head, ears, and face, occasionally extending one or more of her claws to comb straight any matted hair that the foot-cushion cannot bring smooth, in the same way as she uses her long tusks in the parts within their reach.

The chief and most efficient cleaning instrument of the cat, however, is her tongue, which is constructed somewhat after the manner of a currycomb, or rather of a wool-card, being beset with numerous horny points, bent downwards and back

wards, and which serve several important purposes, such as lapping milk, and filing minute portions of meat from bones.

Magnified view of a portion of the upper surface of the Cat's Tongue.

But what falls chiefly to be noticed here, is its important use in keeping the fur smooth and clean; and cats are by no means sparing in their labour to effect this. The female cat is still more particular with her kittens than herself, and always employs a considerable portion of her time in licking their fur smooth. The little things themselves, also, begin, when only a few days old, to perform the office for themselves; and I have observed the half-fledged nestlings of the black cap (Sylvia atricapilla), and a few other birds, preening their feathers as dexterously almost as their dam herself could have done.

It requires the employment of a microscope of considerable power, to observe the very beautiful structure of the foot of the two-winged flies (Muscida), which still more closely resembles a currycomb, than the tongue of the cat does. This structure was first minutely investigated by Sir Everard Home and Mr. Bauer, in order to explain how these insects can walk upon a perpendicular glass, and can even support themselves against gravity. Of the structure of the foot of flies, considered as an instrument for cleaning, I have not hitherto met with any description in books of natural history, though most people may have remarked flies to be ever and anon brushing their feet upon one another, to rub off the dust, and equally assiduous in cleaning their eyes, head, and corslet with their forelegs, while they brush their wings with their hind legs. In the common blow-fly (Musca carnaria), there are two rounded combs, the inner surface of which is covered with down, to serve the double purpose of a fine brush, and to assist in forming a vacuum when the creature walks on a glass, or on the ceiling of a room. In some species of another family (Tipulidae), there are