In certain parts of Paraguay, especially in the Tarumensian territory, you meet with another species of fly. In size and shape they differ little from our common flies, but are of a white colour, and have a formidable sting, which, when inserted into the flesh of man or beast, elicits a quantity of blood. I scarce ever remember seeing them in houses; they chiefly infest the roads, where they are excessively troublesome to horse travellers. There is a great number and variety of gad-flies, in plains adjacent to woods, but these insects attack beasts only. I am not surprized at the fable of Io being driven mad by a gad-fly, having so often seen horses and mules, tractable at other times, tormented by gad-flies adhering to their skin like leeches, till they grew quite furious, and lost all control over themselves, and regard for their riders. Still greater danger is experienced in the woods from certain large wasps, the sting of which perfectly infuriates the horses. To free themselves from these cruel tormentors, they often refuse to obey the bridle, and throw their rider, rushing onwards, and rolling themselves on the ground; a circumstance which occasions many broken legs, and bruised heads, and much bloodshed. I, myself, though riding on a very gentle mule, should have been killed once owing to this circumstance, had not an Indian come to my assistance. These insects attack men also. Their sting occasions violent pain and great swelling. A piece of fresh turf is generally applied to the wounded part, by way of remedy, but it never did me any good, as my cheek may testify. In my absence, a great number of wasps flew into the yard of our house, and settled upon a stake, forming themselves into a large round ball. Lest passers-by should disperse them, and they should fly into our apartment, I fired a gun into the ball of wasps. Terrified at the sudden report, they all flew away except one, which pitched upon my face, and inserting its sting into the flesh, caused it to swell dreadfully. The tumour was succeeded by a corresponding degree of pain. On my complaining the next day, and mentioning the remedies I had used, an old Abipon said, "Why did you not anoint the swelling with beef fat, Father? that is an old and certain remedy amongst us." I complied with this advice, in consequence of which the swelling and pain both ceased. Take notice that I do not mean suet, but the fat of the animal, which is used in Paraguay in the place of melted butter. How dangerous it is to provoke hornets, we have often found in travelling. A nest of these insects concealed under the leaves had perhaps been disturbed unintentionally by the Indians, who preceded me as we were walking in the woods; but they did not escape with impunity, not a few being stung by the hornets dispersed in this manner. Most of them, however, rushed under my clothes, and would have stung me all over, had I not given my garment to the Indians to examine and shake.