Usually appears in compounds: 狐狸 (húli, fox), 狐疑 (húyí, suspicious), 狐臭 (húchòu, body odor). Standalone 狐 is more literary. In Chinese folklore, 狐狸精 (fox spirit) is a seductive shape-shifting demon.
犭 is the dog radical 犬 in left-side form, also used for canids and other beasts. It tags 狐 as a four-legged animal, grouping it with 狗 (dog), 猫 (cat), and 狼 (wolf).
瓜 supplies the reading, drifting from guā to hú along an old velar alternation. The same phonetic surfaces in 弧 (arc) and 孤 (orphan), and the wedge-tailed shape of a fox does echo the curving silhouette of a melon on the vine.