These periodical rains, which in themselves constitute one of the wonders of nature, produce another which is almost equally extraordinary; for, as soon as the fat, black earth of the mountains of Abyssinia becomes saturated with water, immense swarms of flies burst into existence; and, with the rains, assist in driving almost every living creature from them. This insect, called by the Abyssinians tsaltsalya, although it is scarcely larger than a common bee, becomes formidable from its immense numbers; and the buzzing sound announcing its arrival is no sooner heard, than the cattle forsake their food and run wildly about the plain, till they actually die from fear, pain, and fatigue. The camel, whose patience under every other affliction is proverbially unalterable, becomes ungovernable from the violent punctures of these flies; his body is soon covered with lumps, which break and putrify, and the wretched creature sinks and dies. Even the rhinoceros and elephant, whose hides are considered almost impenetrable to a musket-ball, are severely persecuted by these insects; but they instinctively fortify themselves against their attack by wallowing in the mud, which, when dried by the sun, forms a coating that is impenetrable to their stings. All the inhabitants of Melinda, down to Cape Gardfui, Saba, and the south coast of the Red Sea; and all those of the countries from the mountains of Abyssinia to the confluence of the Nile and the Astaboras, are obliged annually to quit the region of black earth, and, driving their cattle before them, to seek refuge in the cheerless sands of the desert; and so many human beings and huge animals thus flying before an army of little flies, certainly forms a very remarkable and surprising feature in the great picture of Nature. Of all the writers on these countries, Isaiah is, we believe, the only one, before Bruce, who has given an account of this insect. "And it shall come to pass," says the prophet, "in that day, that the Lord shall hiss for the fly that is in the uttermost parts of the rivers of Egypt, and they shall come and shall rest all of them in the desolate valleys."