Males are slightly smaller (body length 29 millimetres (1.1 in)) and have dark brown wings, which are absent in females.

It is stoutly built, with a reddish head and brown to black body segments with prominent yellow margins.

[1] The femora are heavily spined, with the hind tibiae having two very broad ridges with only two rows of spurs.

Family groups are found in late summer and autumn: a brood of black nymphs, a wingless female and two or more males, all living in a hidden crack.

[2] When alarmed, it raises its abdomen into the air and squeaks loudly;[1][3] it also releases a foul-smelling liquid from glands on the back [2] when handled and alarmed, producing an indelible brown stain on skin.