The cotton bollworm is very variable in both size and colour. The body length varies between 12 millimetres (0.47 in) and 20 millimetres (0.79 in) with a wingspan of 30–40 millimetres (1.2–1.6 in). The forewings are yellowish to orange in females and greenish-gray in males, with a slightly darker transversal band in the distal third. The external transversal and submarginal lines and the reniform spot are diffused. The hind wings are a pale yellow with a narrow brown band at the external edge and a dark round spot in the middle.