than the other: they extended and contracted themselves at pleasure; and had, in addition, a leaping motion, for they frequently sprung full half an inch from the paper on which he examined them. The ears of wheat were put into water, with gauze tied round them; but, notwithstanding this care, the flies escaped, after their development, without being seen. Mr. Marsham wrote to several friends, requesting their attention to this subject; in consequence of which, an accurate investigation was immediately set on foot.

It appears that these larvæ take their station in the longitudinal furrow of the grain, to the bottom of which they seem attached. Here probably sucking the milky juice which swells the grain, and thus depriving it of part, and in some cases, perhaps, of the whole of its moisture, they occasion it to shrink up, and become what the farmers call pungled. They infect several grains in the same ear, and some ears have been observed, in which even a fourth of the grain was either destroyed, or very greatly injured by them. The latesown wheat always appeared the most infected: this was, no doubt, occasioned by the seed of that sown earlier having obtained too great a degree of hardness, before the insects came out, to be liable to injury.

The Rev. Mr. Kirby carefully investigated the habits of these insects; but it was some time before he was able to discover the parent flies, and still longer before he could find them in sufficient number, to allow him to make the necessary observations as to their habits and economy.

In the beginning of June, 1798, however, he chanced to walk through a corn-field in the evening, and, to his great surprise, he observed an innumerable multitude of them flying about in every direction; and, for nearly a month afterwards, he found them in the greatest abundance. They were seldom seen before seven o'clock; at eight the fields appeared to swarm with them, at which hour they were all busily engaged in laying their eggs; and about nine they generally disappeared.

They were so extremely numerous, that if each of them were to have laid its eggs in a different floret, and these eggs had been permitted to produce larvæ, more than half the grain of the adjacent country would have been destroyed. Twelve Wheat-flies have been observed at the same moment laying their eggs in the same ear; but, among all these myriads, not one male could be discovered. During the day-time none of these insects are to be seen, as they then continue lodged, in a state of repose, upon the lower part of the stem. Upon shaking the stalks, however, they will fly about. The female lays her eggs by means of a long retractile tube, which unsheaths an aculeus as fine as a hair, and very long.

These insects would soon become of serious injury to mankind, were not their race kept within due bounds by several natural enemies: some of these devour them, and others (Ichneumon Tipula) deposit their eggs in the larvæ, the young of which, when hatched there, find a proper nourishment in the bodies of their hosts. This ichneumon is about the size of a Wheat-fly: and in order to observe the manner of the female's depositing her eggs in the caterpillars of the Wheat-fly, Mr. Kirby placed a number of the latter on a sheet of white paper, and then set an ichneumon down in the midst of them. She soon discovered one of the larvæ; when, vibrating her antennæ in an intense degree, she fixed herself upon it, and, bending her abdomen obliquely under her breast, inserted her aculeus into the body of her victim, and there deposited an egg. This being done, she went to a second, which was constrained to undergo the like operation, and so on to all the rest. She never deposited more than one egg in each larva; and when she mounted a larva that had been pricked before, she soon discovered her mistake and left it.

The size of the two insects is so nearly alike, that one young-one only can be nourished by a single larva; and therefore instinct teaches the parent ichneumons to deposit only this number in each,

OF THE FLIES IN GENERAL*.

The appellation of Fly has been given almost exclusively to these insects, probably from their being much more common than any others. The larvæ of some of the species live in water; those of others are found on trees, where they devour aphides or plant-lice; and others in putrid flesh, cheese, &c. Most of the flies are torpid during the winter, and therefore lay up no provision for their nourishment in the cold season. At the decline of the year, when the mornings and evenings become chilly, many of them come for warmth into houses, and swarm in the windows. At first they appear very brisk and alert; but as they become torpid they seem to move with difficulty, and at last are scarcely able to lift their legs. These seem as if they were glued to the glass; and by degrees many of the insects do actually stick on the glass till they die. It has been observed that some of the flies, besides sharp, hooked nails, have skinny palms or flaps to their feet, by which they adhere to glass and other smooth bodies, and walk on ceilings with their backs downward. They are enabled to do this, by the pressure upon those flaps by the atmosphere; the weight of which they easily overcome in warm weather, when they are brisk and alert. But towards the end of the year this resistance becomes too mighty for their diminished strength; and we see flies labouring along, and lugging their feet on windows as if they stuck fast to the glass; and it is with the utmost difficulty they can draw one foot after another, and disengage their hollow caps from the slippery surface. On a principle exactly similar to this it is, that boys, by way of amusement, carry heavy weights, by only a piece of wet leather at the end of a string, clapped close to the surface of a stone.

The mouth of these insects has a soft, fleshy proboscis, with two equal lips; and the sucker is furnished with bristles. The antennæ are generally very short.

It is a very extraordinary fact, that flies have been known to remain immersed in strong liquors, even for several months, and afterwards, on being taken out, and exposed to the air, have again revived. Some, we are

told by Dr. Franklin, were drowned in Madeira wine, when bottled in Virginia to be sent to England. At the opening of a bottle of this wine at a friend's house in London, many months afterwards, three drowned flies fell into the first glass that was filled. The Doctor says, that having heard it remarked that drowned flies were capable of being revived by the rays of the sun, he proposed making the experiment. They were therefore exposed to the sun, upon the sieve which had been employed to strain them from the wine. In less than three hours two of them, by degrees, began to exhibit signs of life. Some convulsive motions were first observed in the thighs; and at length they raised themselves upon their legs, wiped their eyes with their forefeet, and, soon afterwards, flew away. The Rev. Mr. Kirby informs me, that he has made the same observation on flies taken out of home-made wines. He says that many have recovered, after having been twelve months immersed.

THE COMMON FLESH-FLY*.

It is a fact not generally known, that this is a vivipa

DESCRIPTION. The Common Flesh-fly is, in appearance, much allied to the large Blue-bottle Flesh-flyt. It is, however, somewhat more slender, and is besides of a grayish tint, occasioned by some irregular and rather long stripes on the corselet running lengthwise, and some still more irregular marks of the same kind on the body; all of them of a cinereous gray colour, separated by a shining brown, which, under certain points of view, appear of a bluish tint. Its legs are black; and the halteres, or balancers under its wings, are whitish; and its reticular eyes are somewhat red.

SYNONYMS. Musca carnaria. Linn.-La Mouche carnassier, in France.-La Mouche vivipare. Cuvier.

rous insect, depositing its offspring, in a living state, on the meat in our shambles and larders. The young-ones appear under the same worm-like form, as the grubs produced from the Blue Flesh-fly. They feed as those do, increase in size, undergo all their transformations in the same manner, and even in the fly-state appear but little different.

When the larvæ have attained their full size, (which is generally in seven or eight days,) they quit their . food, and wander in search of loose earth or rubbish, in which they bury themselves, and undergo their metamorphoses.

THE HESSIAN FLY*?

Among the various causes of alarm experienced by the farmer in the course of his rural labours, few are more powerful, though many more justly so, than the larvæ or grubs of this little fly. These are lodged and nourished within the stems of wheat and rye, just above the root, which they entirely destroy.

In order to determine the species of this animal, Mr. Markwick planted some diseased roots of wheat in a small flower-pot filled with bran: this pot he covered with gauze, in such a manner that no insect could get in from the outside, nor any escape from within. Not long afterwards he discovered, on the inside of the gauze, three small flies, which he found to be of this species; and, a few days afterwards, three more. There were in the pot six roots of diseased wheat, which thus produced six flies. On examining the roots, he found an empty chrysalis in each.

DESCRIPTION. This fly is not quite the fourth part of an inch in length. Its thorax is dark-coloured, but marked longitudinally with two yellow lines. The grubs are white, about two lines in length, composed of ten rings, and have the head pointed at the end. The chrysalis is yellow, shining, rather more than one line long, and composed of rings.

SYNONYMS. Musca Pumilionis. Linnæus,