in natural history, a name given by M. Reaumur, and other of the French writers, to a peculiar species of the worms which feed on the pucerons, or aphides. See APHIS.

This worm is more particularly called barbet blanc, as also berillon blanc, or white hedgehog, from its being covered with oblong white tufts of filaments, which stand fland in the manner of the quills of a hedgehog or porcupine. M. Reaumur calls these tufts of filaments, *spines*, not to signify that they are capable of pricking, for they have no such power; but to express their manner of arrangement on the body of the animal.

This creature is of the size of a small fly without its wings; but this tufted covering so much increases the bigness, that it appears of the size of a fly of the largest kind.

These tufts have neither the hardness of spines, nor the consistence of hairs; but they resemble, in their fangy texture, a filament of cotton. All these spines or tufts of cotton are arranged in six lines, as evenly parallel to one another as the shape of the animal's body will permit. Each of these lines reaches over the whole upper part of the body, following the course of one of the rings. The several spines, which compose each line, almost touch one another at their bases; but as they all stand perpendicular, and are placed on a convex surface, they are considerably distant from one another at the points. The tufts on different insects of this species are of different lengths. In the common kinds, they are short, and stand perfectly erect; but in some they are so long, as not to be able to support their own weight, but bend into hooks. In all the species, every single tuft has its irregularities, and is seen to be composed of several cottony filaments of unequal lengths, which are knotty and rough in several places; and when touched, they feel soft like cotton. It is also very remarkable, that, on being touched, they always adhere to the fingers; and are so loofly connected with the body of the animal, that, on rubbing the finger over it ever so lightly, they all come off, and leave it naked. The creature then appears green, and of a very different figure from what it had before; and the tufts lose their figure, and appear only a congeries of round grains of a cottony matter. The sudden change in size and appearance in the creature, makes it look as if it had undergone a transformation.

It is evident from observation, that the matter of which the tufts, which cover the body of this animal, are made, is of a very different nature and formation from the filky filaments which caterpillars and other insects spin out of their entrails. They have all peculiar organs for the spinning it, and all draw it out to any length they please; but this matter, on the contrary, has a determinate length, which it cannot exceed; and is only formed of the matter peripheried through certain parts of the body of the creature, which hardens as it remains in the air. As it is so easy to divest these creatures of their downy covering, it will be readily conceived, that nature must have made its reparation to the animal very easy; and this is indeed the case: for if the animal be wholly made naked, by drawing the finger three or four times over it, it loses its fine green colour in half an hour afterwards, appearing as if dulled over with flour; and, in fine, within the space of twelve hours, is furnished with tufts as long, and every way as large, as those it lost. When the tufts have been rubbed off from one of these animals, and its body is left naked, if it be then examined by a microscope, there will be found a number of small hollows or depressions in the skin, exactly answering in place and number to the cottony-tufts that are to succeed the lost ones. It is to be conceived, that, within each of these hollows, there are a great number of fine apertures, through which the matter that is to form the new tufts is to pass; but these are not distinguishable by the most powerful glasses: if the tufts, however, be examined while forming, they will be found to consist of a vast number of regular filaments, placed close by one another, and each running distinctly the whole length of the tuft: this appearance is, however, wholly lost afterwards, the fine threads sticking to, and intermingling with, one another, and many of them breaking in several places; so that the whole tuft resembles a coarse and jingle filament.

These barbets are found in great plenty on the leaves of the plum-tree in the months of June and July. The puceron of this tree seems more to their taste than any other kind; and they are often found in numbers on every leaf of the tree where these little animals are. The matter of their tufts seems analogous to the downy covering of some of the pucerons, and to no other substance in the animal world. The puceron of the beech-tree has this downy matter running into much longer filaments even than this animal; and, in the several other species, it is found growing to the different lengths from this to a mere downy powder. The barbet lives about a fortnight in that form, and then becomes a chrysalis; from which, after a month, there comes out a small beetle of a dusky brown colour.