Baccha elongata can reach a length of . It is one of the smaller hoverflies, the wing length is around 4.5 to 8 mm. The long, very slender body of these hoverflies is unmistakable. They also differ from other hoverflies by their elongated, thin abdomen ending in club. This club-shaped abdomen is black with a yellow spot on the 3rd and 4th segments. Legs are brownish yellow. Forehead is brightly hairy. Members of the
eristaline genus
Sphegina are also very slender and can be found in similar habitat but those flies have a rather different enlarged hind femur, whereas in
Baccha this feature is slender. As with most hoverfly species the sexes can be told apart by the male's eyes meeting on the top of the head, but separated in the female. This species is very similar to
Baccha obscuripennis Meigen, 1822. ==Biology==