Felix, qui potuit rerum cognoscere causas;
Quique metus omnes, et inexorabile fatum,
Subjecit pedibus, strepitumque Acherontis avari.
Virg. Georg. II. 490.[Back to Canto]
Torva leæna lupum sequitur, lupus ipse capellam,
Florentem cytisum sequitur lasciva capella.
Virg.[Back to Canto]
Fell Oestrus buries, l. 29. The gadfly, bot-fly, or sheep-fly: the larva lives in the bodies of cattle throughout the whole winter; it is extracted from their backs by an African bird called Buphaga. Adhering to the anus it artfully introduces itself into the intestines of horses, and becomes so numerous in their stomachs, as sometimes to destroy them; it climbs into the nostrils of sheep and calves, and producing a nest of young in a transparent hydatide in the frontal sinus, occasions the vertigo or turn of those animals. In Lapland it so attacks the rein deer that the natives annually travel with the herds from the woods to the mountains. Lin. Syst. Nat.[Back to Canto]
The wing'd Ichneumon, l. 33. Linneus describes seventy-seven species of the ichneumon fly, some of which have a sting as long and some twice as long as their bodies. Many of them insert their eggs into various caterpillars, which when they are hatched seem for a time to prey on the reservoir of silk in the backs of those animals designed for their own use to spin a cord to support them, or a bag to contain them, while they change from their larva form to a butterfly; as I have seen in above fifty cabbage-caterpillars. The ichneumon larva then makes its way out of the caterpillar, and spins itself a small cocoon like a silk worm; these cocoons are about the size of a small pin's head, and I have seen about ten of them on each cabbage caterpillar, which soon dies after their exclusion.
Other species of ichneumon insert their eggs into the aphis, and into the larva of the aphidivorous fly: others into the bedeguar of rose trees, and the gall-nuts of oaks; whence those excrescences seem to be produced, as well as the hydatides in the frontal sinus of sheep and calves by the stimulus of the larvæ deposited in them.[Back to Canto]
While fierce Libellula, l. 37. The Libellula or Dragon-fly is said to be a most voracious animal; Linneus says in their perfect state they are the hawks to naked winged flies; in their larva state they run beneath the water, and are the cruel crocodiles of aquatic insects. Syst. Nat.[Back to Canto]
Contending bee-swarms, l. 39. Stronger bee-swarms frequently attack weak hives, and in two or three days destroy them and carry away their honey; this I once prevented by removing the attacked hive after the first day's battle to a distinct part of the garden. See Phytologia, Sect. XIV. 3. 7.[Back to Canto]
The shark rapacious, l. 57. The shark has three rows of sharp teeth within each other, which he can bend downwards internally to admit larger prey, and raise to prevent its return; his snout hangs so far over his mouth, that he is necessitated to turn upon his back, when he takes fish that swim over him, and hence seems peculiarly formed to catch those that swim under him.[Back to Canto]