According to Apple Green Health Network, fleas are not afraid of the smell of toilet water, but of high temperature, strong light and well-ventilated environment. Fleas are small, wingless, jumping parasitic insects; Flat, brown to dark brown; The body wall is hard, with many bristles, thorns and combs; The body is divided into three parts, chest and abdomen, with obvious cross section. Generally, male fleas are smaller than female fleas, and flea larvae are small and slender, maggot-like, milky white, eyeless and footless, and 4.5 mm long.