may remark, however, that both its sight and hearing seem to be still more acute than its touch, for its eyes are more than usually prominent and closely grouped, and the faintest hum of a gnat puts it on the alert. It requires, indeed, no little agility to seize these, particularly the vibrating gnat (Chironomus motitator, FABR.), which we have observed to be its chief prey, as the slightest movement or the faintest noise puts these gnats to flight; and hence we infer that the very long legs of this spider are intended more for pursuit than for feeling*.

Long-legged house spider (Pholcus phalangioïdes).

It appears to us, that a much stronger proof of the acuteness of touch in spiders may be derived from the manner in which they construct their webs. They must use their eyes indeed, in planning their frameworks; but they cannot be guided by sight in the details, for the spinneret, whence they draw their threads, being situated behind, they must depend in a great measure on the tact of this organ for the accuracy of their workmanship. The soft yielding consistency, and the papillary form of this wonderful organ, indeed, seems to indicate its being well adapted for an instrument of touch †. But the claws them* J. R. † See Insect Architecture, page 336-8.

selves must also have this sense in perfection; for in making the various rays as well as the cross lines of a geometric net, the spider always guides the thread from the spinneret by one of its hind claws, which it cannot possibly see with any one of its eyes, as these are all placed forwards on the head. The exquisite workmanship of these webs, thus woven as it were in the dark, indicates that the sense of touch by which alone it can be accomplished must be peculiarly delicate.

In the family of the harvest spiders (Phalangioïda), which have only two eyes, and do not spin webs, the long legs are used not only to escape from enemies and pursue prey, but to explore, by touch, the objects among which they travel. That the very long legs of these insects are endowed with much nervous power, appears from their continuing to move for many hours after being accidentally detached from the body * a circumstance which we have frequently witnessed with wonder, and which could not well occur if these creatures possessed a brain. On the other hand, most beetles, it is probable, and the various moths, make little use of their feet to explore the things around them. There are many other insects, however, which seem to have feet little less exquisitely formed, as organs of touch, than the human hand, if softness and elasticity be taken as the standards of comparison.

The insects to which we allude are those which live among grass and herbage, comprehending a few beetles (Chrysomelidæ, &c.), most two-winged flies (Diptera), and, if we mistake not, all the crickets and grasshoppers (Gryllidæ, &c.) The foot of the common fly has been shown by Sir Everard Home and Mr. Bauer to be admirably adapted for climbing upon *Latreille, Monographie des Faucheurs, Hist. des Fourmis, page 371.

glass, even when the body hangs downwards *, and it is also finely adapted, both as a brush and as a comb, for cleaning the body and wings t; but it is no less fitted for being an organ of touch, from its softness and flexibility. Amongst the locusts (Locustida), however, this structure is more conspicuous from the greater size of the insects, the terminal portion of the foot being not only furnished with a moveable claw, but with two soft round palms, if we may call them so, which must greatly assist in feeling the nature of the surface over which the insect walks. Even in insects of smaller size, as the musk beetle (Cerambyx odoratus, DE GEER), and the catch-weed

* See Insect Transformations, p. 390-1. It is right to mention that a paper has been recently read at the Linnæan Society, in which the principle of suction, by which the fly is said to hold on against gravity, is disproved. See Taylor's Philosophical Magazine.

† J. Rennie, in Journal of Royal Institution, for Oct. 1830.

beetle (Timarcha tenebricosa, MEGERLE), this structure of the feet is very obvious without the aid of a glass, which is required in observing the palms of the two-winged flies (Diptera).

In some other beetles, again, whose horny covering would seem to preclude them from possessing the means of touch over the surface of their body like the softer animals, and which even have their legs equally horny and stiff, we may observe, that a beautiful provision is made for the sense of touch in a long, manyjointed, flexible claw at the termination of the foot. This is particularly remarkable in the common dung beetle (Geotrupes stercorarius), in which the flexibility and easy motion of the jointed claw contrasts strikingly with the apparently awkward stiffness of the other joints, and indeed of the whole body.

According to the greater number of naturalists, however, the two chief organs of touch in insects are the antennæ and palpi, both of which have been in popular language termed feelers. Latreille calls the palpi antennules*. Leaving the antennæ to be discussed in our chapter on Hearing, we shall only at present attend to the palpi, which are usually four in number. These organs are small and generally cylindrical, consisting of from one to six joints, one palpus being implanted in each of the two lower jaws, and the remaining two being attached to the lower lip, as exhibited in p. 43, fig. a. The former, or upper pair, are, in most cases, a joint longer than the under, so as that they may all four, when bent down, reach to the ground at the same time. They are most commonly smooth, and end in a softish point; but in some cases they are covered with hair (Copris, Cicindela, &c.). The only organs, in the higher animals, which seem analogous to these, are the whiskers (Vibrissæ) in the cat, the seal, and the night* Règne Animal, iv. 301, edit. 1829.

jar (Nytichelidon Europeus, RENNIE), and the appendages at the lips of the cod-fish (Gadus morhua), the surmullet (Mullus barbatus), and some others. This want of analogous organs in other animals of course renders our investigation of the use of the palpi in insects much more difficult.

aud auch the yarn yout sads an

Stag beetle (Lucanus Cerus) on the wing.

a a The four palpi, or antennules.

Bonsdorf, in his singular tract upon the use of the palpi, endeavours to show that they are organs of smell*; Knoch imagined that the upper pair were * De Fabr. et Usu Palporum in Insectis.