A collision between a semi-truck and a motorcyclist is leaving a Shelby County man dead.  The accident happened Thursday just after 11am on North Brush College Road in Decatur.  Macon County Coroner Michael Day says the semi was pulling into a drive near ADM when it struck the motorcycle.  The 58-year old Lakewood man on the bike died at the scene.  The semi driver was not harmed.  Names are being withheld pending notifications.