The rosalia longicorn is one of the most striking and elegant of all beetles, with its beautiful steely blue-grey colouration and large, dominating black spots (4). The extremely long antennae on the front of the head are also adorned with groups of black hairs, which contrast dramatically with the blue-sky colour of the bare parts, appearing as alternating bands of black and blue (3) (4). Males can be distinguished from females by their longer antennae, which can greatly exceed the length of the body (3).