As might be expected for such a large family, considerable variation exists among the species.
Sizes range from <1 to 35 mm (1.4 in), with most in the 2–8 mm range, and the form is generally elongated, with some rove beetles being ovoid in shape.
Colors range from yellow and red to reddish-brown to brown to black to iridescent blue and green.
The antennae  usually have 11 segments and are filiform, with moderate clubbing in some genera.
The abdomen may be very long and flexible, and some rove beetles superficially resemble earwigs.

Some members of Paederina (specifically the genus Paederus), a subtribe of Paederinae, contain a potent vesicant in their haemolymph that can produce a skin irritation called dermatitis linearis,, also known as Paederus dermatitis.
The irritant pederin is highly toxic, more potent than cobra venom.
As might be expected for such a large family, considerable variation exists among the species. Sizes range from <1 to 35 mm (1.4 in), with most in the 2–8 mm range, and the form is generally elongated, with some rove beetles being ovoid in shape. Colors range from yellow and red to reddish-brown to brown to black to iridescent blue and green. The antennae  usually have 11 segments and are filiform, with moderate clubbing in some genera. The abdomen may be very long and flexible, and some rove beetles superficially resemble earwigs.
Some members of Paederina (specifically the genus Paederus), a subtribe of Paederinae, contain a potent vesicant in their haemolymph that can produce a skin irritation called dermatitis linearis,, also known as Paederus dermatitis. The irritant pederin is highly toxic, more potent than cobra venom.
Rove beetle