1) Genus sistrurus 2) Pygmy rattlesnakes 3) Reptile genus 4) Reptile of the United States 
Sistrurus is a genus of venomous pit vipers found in Canada, the United States and Mexico. The name is a Latinized form of the Greek word for `tail rattler` (Σείστρουρος, Seistrouros) and shares its root with the ancient Egyptian musical instrument, the sistrum, a type of rattle. Three species are currently recognized. Sistrurus speci.....
(from the article `rattlesnake`) ...Crotalus, including the small North American sidewinder (C. cerastes). The other three species belong to a more primitive genus, Sistrurus, which ...
(sis-troo´rәs) a genus of small rattlesnakes widely distributed throughout the United States, having symmetrical plates covering their heads.
[n] - pygmy rattlesnakes
genus Sistrurus noun pygmy rattlesnakes