The species is endemic to Asia and northern Africa.

S. diadema is found in Algeria, Afghanistan, Egypt, northern India, Iran, Iraq, Israel,[3] Lebanon, Jordan, southern Kazakhstan, Kyrgyzstan, Libya, Mali, Mauritania, Morocco, Niger, Oman, United Arab Emirates, western Pakistan, Russia, Saudi Arabia, northern Sudan, Syria, Tajikistan, Tunisia, Turkey, southern Turkmenistan, and Uzbekistan.

Clifford Cocq van Breugel " who was Dutch consul at Tripoli,[4] probably referring to Jacques Fabrice Herman Clifford Kocq van Breugel (1799-1867).

S. diadema may attain a total length of 1.8 m (about 6 feet), of which about 34 cm (13½ inches) is tail.

Ventrally, it is usually uniform white, but rarely has small blackish spots.