This fly was so grievous a pest that the Phoenicians invoked against it the aid of their god Baal-zebub. 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.
The Septuagint (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.”