"In all those instances in which I observed them, the green flies were the first to attack, and this is the common opinion among the shepherds. After a time, when the larvæ (maggots) commenced gnawing the flesh, the putrid stench, which was thereby occasioned, attracted numerous other species. The _Vomitoria_ (_blue-bottle_) was very common, more numerous than both the former species, and perhaps contributed most to accelerate the death of the animal, after the others had commenced. The _Carnaria_ was rare. I observed but few of them, and these seemed not concerned; which is the more remarkable, as in the fenny counties of England it is said to be most troublesome. All the species of this genus resemble one another closely, both in appearance and mode of life. They are exceedingly voracious, feeding upon carcasses and filth of every description. In five days after being hatched they arrive at full growth, provided they have plenty of food; they then cease to eat, and seek to assume the pupa state, crawling under ground two or three inches. Here they remain about fourteen days, when the shell cracks, and the imago, or fly, appears. In this last state, they feed also on putrid juices, sucking them through their probosces." The correctness of this description of their transformations I can attest, from having watched their habits during my anatomical pursuits in the summer months. (148.) _Treatment of Fly-blown Sheep._ When the sheep is fly-blown, dislodge the maggots with a knife, and shake a little powdered white lead into the wound. Do not apply tar to the abraded surface, as, from its cauterizing effects, the wound will be enlarged, and a repetition of the visit speedily ensured. To ward off the onset of the flies, various substances noxious to them are rubbed or poured upon the wool. Tar, in small quantities, and of pungent quality, is by some daubed upon the ears, horns, and tail. Others prefer rubbing a little melted butter, thickened by flour of sulphur, along the sheep's back: this is an effectual preventive. Some, again, prefer dressing the sheep, when in low situations, with the following recipe, which I take the liberty of copying from Mr Mather's paper on the fly, in the _Quarterly Journal of Agriculture_, No. XXIV. "Take of Arsenic, finely pounded, one pound Potash twelve ounces, Common yellow soap six ounces, Rain or river water thirty gallons.