Albert Barnes Commentary Leviticus 11:42

"Whatsoever goeth upon the belly, and whatsoever goeth upon all fours, or whatsoever hath many feet, even all creeping things that creep upon the earth, them ye shall not eat; for they are an abomination." — Leviticus 11:42 (ASV)

Whatsoever goeth upon the belly - that is, all footless reptiles, and mollusks, snakes of all kinds, snails, slugs, and worms. “Whatsoever goeth upon all four”; that is, “creeping things,” or vermin; such as the weasel, the mouse, or the lizard. Whatsoever hath more feet; that is, all insects, except the locust family (Leviticus 11:22 note), myriapods, spiders, and caterpillars.