Another quadruped contributing greatly to our domestic comfort, from which we derive a considerable portion of our animal food, and which, on account of its patient and laborious character when employed in agriculture, is an excellent substitute for the horse, (you will directly perceive I am speaking of the ox, whether male or female,) is also not exempt from insect domination. At certain seasons the whole terrified herd, with their tails in the air, or turned upon their backs, or stiffly stretched out in the direction of the spine, gallop about their pastures, making the country re-echo with their lowings, and finding no rest till they get into the water. Their appearance and motions are at this time so grotesque, clumsy, and seemingly unnatural, that we are tempted rather to laugh at the poor beasts than to pity them, though evidently in a situation of great terror and distress. The cause of all this agitation and restlessness is a small gad-fly (Œ. Bovis), less than the horse-bee, the object of which, though it be not to bite them, but merely to oviposit in their hides, is not put into execution without giving them considerable pain.
When oxen are employed in agriculture, the attack of this fly is often attended with great danger, since they then become perfectly unmanageable; and, whether in harness or yoked to the plough, will run directly forward. At the season when the Œstrus infests them, close attention should be paid, and their harness so constructed that they may easily be let loose.
Reaumur has minutely described the ovipositor, or singular organ by which these insects are enabled to bore a round hole in the skin of the animal and deposit their eggs in the wound. The anus of the female is furnished with a tube of a corneous substance, consisting of four pieces, which, like the pieces of a telescope, are retractile within each other. The last of these terminates in five points, three of which are longer than the others, and hooked: when united together they form an instrument very much like an auger or gimlet; only, having these points, it can bite with more effect[240]. He thinks the infliction of the wound is not attended by much pain, except where very sensible nerves are injured, when the animal, appearing to be seized with a kind of phrensy, begins to gambol, and run with such swiftness that nothing can stop it. From this semblance of temporary madness in oxen when pursued and bored by the Œstrus, the Greeks applied the term to any sudden fit of fury or violent impulse in the human species, calling such ebullitions an Œstrus. The female fly is observed to be very expeditious in oviposition, not more than a few seconds; and while she is performing the operation, the animal attempts to lash her off, as it does other flies, with its tail. The circular hole, made by the auger just described, always continues open, and increases in diameter as the larva increases in size; thus enabling it to receive a sufficient supply of air by means of its anal respiratory plates, which are usually near the orifice.—But though these insects thus torment and terrify our cattle, they do them no material injury. Indeed they occasion considerable tumours under the skin, where the bots reside, varying in number from three or four to thirty or forty; but these seem unattended by any pain, and are so far from being injurious, that they are rather regarded as proofs of the goodness of the animal, since these flies only attack young and healthy subjects. The tanners also prefer those hides that have the greatest number of bot-holes in them, which are always the best and strongest[241].
The Stomoxys, and several of the other flies before enumerated, as well as the dog and American ticks, are as prejudicial to the ox as to the horse. One species of Hippobosca I have reason to believe is appropriated to them; yet, since a single specimen only has hitherto been taken[242], little can be said with respect to it.—A worse pest than any hitherto enumerated, is a minute fly, concerning the genus of which there is some doubt, Fabricius considering it as a Rhagio, (R. columbaschensis,) and Latreille as a Simulium[243]; but to whatever genus it may belong, it is certainly a most destructive little creature. In Servia and the Bannat it attacks the cattle in infinite numbers, penetrates, according to Fabricius, their generative organs, but according to other accounts their nose and ears, and by its poisonous bite destroys them in the short space of four or five hours. Much injury was sustained in 1813 from this insect in the palatinate of Arad in Hungary and in the Bannat; in Banlack not fewer than two hundred horned cattle perishing from its attacks, and in Versetz, five hundred. It appears towards the latter end of April or beginning of May in such indescribable swarms as to resemble clouds, proceeding as some think from the region of Mehadia, but according to others from Turkey. Its approach is the signal for universal alarm. The cattle fly from their pastures; and the herdsman hastens to shut up his cows in the house, or, when at a distance from home, to kindle fires, the smoke of which is found to drive off this terrible assailant. Of this the cattle are sensible, and as soon as attacked run towards the smoke, and are generally preserved by it[244].
Tabani in this country do not seem to annoy our oxen so much as they do our horses: perhaps for this immunity they may be indebted to the thickness of their hides; but Virgil's beautiful description of the annoyance that the Grecian Œstrus, called by the Romans Asilus, belongs evidently to one of the Tabanidæ. As the passage has not been very correctly translated, I shall turn poet on the occasion, and attempt to give it you in a new dress.
Through waving groves where Selo's torrent flows,
And where, Alborno, thy green Ilex grows,
Myriads of insects flutter in the gloom,
(Œstrus in Greece, Asilus named at Rome,)
Fierce and of cruel hum. By the dire sound
Driven from the woods and shady glens around
The universal herds in terror fly;
Their lowings shake the woods and shake the sky,
And Negro's arid shore——
In some parts of Africa also insects of this tribe do incredible mischief. What would you think, should you be told that one species of fly drives both inhabitants and their cattle from a whole district? Yet the terrible Tsaltsalya or Zimb of Bruce (and the world seems now disposed to give more credit to the accounts of that traveller) has power to produce such an effect. This fly, which is a native of Abyssinia, both from its habits and the figure, appears to belong to the Tabanidæ, and perhaps is congenerous with the Œstrus of the Greeks[245].
Small as this insect is, we must acknowledge the elephant, rhinoceros, lion and tiger vastly his inferior. The appearance, nay the very sound of it occasions more trepidation, movements and disorder both in the human and brute creation, than whole herds of the most ferocious wild beasts in tenfold greater numbers than they ever are would produce. As soon as this plague appears, and their buzzing is heard, all the cattle forsake their food, and run wildly about the plain till they die worn out with fatigue, fright, and hunger. No remedy remains for the residents on such spots but to leave the black earth and hasten down to the sands of Atbara, and there they remain while the rains last. Camels, and even elephants and rhinoceroses, though the two last coat themselves with an armour of mud, are attacked by this winged assassin and afflicted with numerous tumours. All the inhabitants of the sea-coast of Melinda down to Cape Gardefui, to Saba and the south of the Red Sea, are obliged in the beginning of the rainy season to remove to the next sand to prevent all their stock of cattle from being destroyed. This is no partial emigration—the inhabitants of all the countries from the mountains of Abyssinia northward, to the confluence of the Nile and Astaboras, are once a year obliged to change their abode and seek protection in the sands of Beja; nor is there any alternative or means of avoiding this, though a hostile band were in the way capable of spoiling them of half their substance[246]. This fly is truly a Beelzebub[247]: and perhaps it was this, or some species related to it, that was the prototype of the Philistine idol worshiped under that name and in the form of a fly.
I must not conclude this subject of insects hurtful to our cattle, without noticing a beetle much talked of by the ancients for its mischievous properties in this respect. You will soon and rightly conjecture that I am speaking of the Buprestis[248], so called from the injury which it has been supposed to occasion to oxen or kine.