Heb. zebub, (Eccl. 10:1; Isa. 7:18). This fly was so grievous a
pest that the Phoenicians invoked against it the aid of their
god Baal-zebub (q.v.). The prophet Isaiah (7:18) alludes to some
poisonous fly which was believed to be found on the confines of
Egypt, and which would be called by the Lord. Poisonous flies
exist in many parts of Africa, for instance, the different kinds
of tsetse.

Heb. 'arob, the name given to the insects sent as a plague on
the land of Egypt (Ex. 8:21-31; Ps. 78:45; 105:31). The LXX.
render this by a word which means the "dog-fly," the cynomuia.
The Jewish commentators regarded the Hebrew word here as
connected with the word "'arab", which means "mingled;" and they
accordingly supposed the plague to consist of a mixed multitude
of animals, beasts, reptiles, and insects. But there is no doubt
that "the "'arab"" denotes a single definite species. Some
interpreters regard it as the Blatta orientalis, the cockroach,
a species of beetle. These insects "inflict very painful bites
with their jaws; gnaw and destroy clothes, household furniture,
leather, and articles of every kind, and either consume or
render unavailable all eatables."