Albert Barnes Commentary Joel 2:4

"The appearance of them is as the appearance of horses; and as horsemen, so do they run." — Joel 2:4 (ASV)

The appearance of them, is as the appearance of horses. — “If you carefully consider the head of the locust,” says Theodoret, a Bishop in Syria, “you will find it exceedingly like that of a horse.”

This is why the Arabs, of old and to this day, say: “In the locust, slight as it is, is the nature of ten of the larger animals: the face of a horse, the eyes of an elephant, the neck of a bull, the horns of a deer, the chest of a lion, the belly of a scorpion, the wings of an eagle, the thighs of a camel, the feet of an ostrich, the tail of a serpent.”