Shen Collection, Middle Volume. Radical: Insect (chóng). Character: fu. Kangxi strokes: 11. Page 1079, Entry 26.
Pronounced fu (falling tone).
Fu snake refers to the scales arranged horizontally under the belly of a snake, which it uses to crawl.
Zhuangzi (Zhuangzi), Chapter on the Equality of Things: Shall I wait for the scales of a snake or the wings of a cicada? Annotation: Fu refers to the uneven part under a snake's belly that helps it crawl.
Also, in the Er Ya (Erya), Interpretation of Fishes: Fu luo, which is the slug. Annotation: This is the snail. For details, see the entry for the character yu.
Also, according to the Collected Rhymes (Jiyun), pronounced pu (falling tone). The meaning is the same.
Textual research: In the Er Ya (Erya), Interpretation of Insects: Fu luo, which is the slug. Following the original book, changed Interpretation of Insects to Interpretation of Fishes.