What is one of a group of metameric hydrocarbons, C5H10, of the ethylene series. The colorless, volatile, mobile liquid commonly called amylene is a mixture of different members of the group called?

amylene — One of a group of metameric hydrocarbons, C5H10, of the ethylene series. The colorless, volatile, mobile liquid commonly called amylene is a mixture of different members of the group. (Webster's 1913.)