Hastings' Dictionary of the Bible (1898)
FLY, the name of a large tribe of insects, some of which are exceedingly annoying and destructive, Isa 7:18. They abound in Egypt and Palestine. One species, which is found by modern travellers in the vicinity of the Nile, and called the Abyssinian fly, is as large as a bee, and is such an annoyance to cattle and other large animals as to oblige them to forsake their pastures and ranges, and to flee to some place where they can roll themselves in
the mud or sand. Hence we may judge of the terrible nature of the judgments mentioned in Ex 8:24; Isa 7:18; in which last passage we are informed that the fly shall be found in the very places to which the cattle resort to rid themselves of its presence.