is also the name of a genus of flies of the hymenoptera order. The mouth is armed with jaws, without any tongue; the antennae have above 30 joints; the abdomen is generally petiolated, joined to the body by a pedicle or stalk; the tail is armed with a fling, which is inclosed in a double-valved cylindrical sheath; the wings are lanceolated and plain. This genus is exceedingly numerous. In Gmelin's or the 13th edit. of the Systema Naturae, no fewer than 415 species are enumerated. They are divided into fa- ICHNEUMON families, from the colour of their scutellum and antennae, as follow: 1. Those with a whitish scutcheon, and antennae annulated with a whitish band. 2. Those which have a white scutcheon, and antennae entirely black. 3. With a scutcheon of the same colour as the thorax; the antennae encompassed with a fillet. 4. With a scutcheon of the same colour as the thorax; and antennae black and setaceous. 5. With setaceous clay-coloured antennae. 6. With small filiform antennae, and the abdomen oval and slender.

One distinguishing and striking character of these species of flies is the almost continual agitation of their antennae. The name of Ichneumon has been applied to them, from the service they do us by destroying caterpillars, plant-lice, and other insects; as the ichneumon or mangouste destroys the crocodiles. The variety to be found in the species of ichneumons is prodigious: among the smaller species there are males who perform their amorous preludes in the most passionate and gallant manner. The posterior part of the females is armed with a wimple, visible in some species, no ways discoverable in others; and that instrument, though too fine, is able to penetrate through mortar and plaster: the structure of it is more easily seen in the long-wimbled fly. The food of the family to be produced by this fly is the larva of wasps or mason-bees; for it no sooner espies one of those nests, but it fixes on it with its wimple, and bores through the mortar of which it is built. The wimple itself, of an admirable structure, consists of three pieces; two collateral ones, hollowed out into a gutter, serve as a sheath, and contain a compact, solid, dentated stem, along which runs a groove that conveys the egg from the animal, who supports the wimple with its hinder legs, lest it should break, and by a variety of movements, which it dexterously performs, it bores through the building, and deposits one or more eggs, according to the size of the ichneumon, though the largest drop but one or two. Some agglutinate their eggs upon caterpillars; others penetrate through the caterpillar's eggs, though very hard, and deposit their own in the inside. When the larva is hatched, its head is so situated, that it pierces the caterpillar, and penetrates to its very entrails. These larvae pump out the nutritious juices of the caterpillar, without attacking the vitals of the creature; who appears healthy, and even sometimes transforms itself to a chrysalis. It is not uncommon to see those caterpillars fixed upon trees, as if they were sitting upon their eggs, and it is afterwards discovered that the larvae, which were within their bodies, have spun their threads, with which, as with cords, the caterpillars are fastened down, and so perish miserably. The ichneumons performed special service, in the years 1731 and 1732; by multiplying in the same proportion as did the caterpillars, their larvae destroyed more of them than could be effected by human industry. Those larvae, when on the point of turning into chrysalids, spin a silky cocoon. Nothing is more surprising and singular, than to see those cocons leap when placed on the table or hand. Plant-lice, the larvae of the curculiones, and spider's eggs, are also sometimes the cradle of the ichneumon-fly. Carcasses of plant-lice, void of motion, are often found on rose-tree leaves; they are the habitation of a small larva, which, after having eaten up the entrails, destroys the springs and inward economy of the plant-louse, performs its metamorphosis under shelter of the pellicle which enfolds it, contrives itself a small circular outlet, and falls forth into open air. There are ichneumons in the woods, who dare attack spiders, run them through with their sting, tear them to pieces, and thus avenge the whole nation of flies of so formidable a foe: others, destitute of wings (and those are females), deposit their eggs in spiders' nests. The ichneumon of the bedeguar, or sweet-briar sponge, and that of the rose-tree, perhaps only deposit their eggs in those places, because they find other insects on which they feed. The genus of the ichneumon-flies might with propriety be termed a race of diminutive canibals.

ICHOGRAPHY, in perspective, the view of anything cut off by a plane, parallel to the horizon, just at the base of it.—The word is derived from the Greek ἰχνος footstep, and ἱστορεῖ I write, as being a description of the footsteps or traces of a work.

Among painters it signifies a description of images or of ancient statues of marble and copper, of busts and semi-busts, of paintings in fresco, mosaic works, and ancient pieces of miniature.