The largest of scorpions, but not the longest, the emperor scorpion (Pandinus imperator) has a dark body ranging from dark blue/green through brown to black. The large pincers are blackish-red and have a granular texture. The front part of the body, or prosoma, is made up of four sections, each with a pair of legs. Behind the fourth pair of legs are comb-like structures known as pectines – these are longer in males and can be used by man to distinguish the sexes. The tail, known as the metasoma, is long and curves back over the body. It ends in the large receptacle containing the venom glands and tipped with the sharp, curved sting. Sensory hairs cover the pincers and tail, enabling the scorpion to detect prey through air and ground vibrations. When gravid (pregnant), the body of a female expands to expose the whitish membranes connecting the segments. The emperor scorpion fluoresces greenish-blue under ultraviolet light.