who described it?
American entomologist Thomas Say
Colorado potato beetle
The Colorado potato beetle was first observed in 1811 by Thomas Nuttall and was formally described in 1824 by American entomologist Thomas Say. 
where did the colorado potato beetle come from It is native to America.
wiki:13312136
Colorado potato beetle [SEP] Taxonomy
The Colorado potato beetle was first observed in 1811 by Thomas Nuttall and was formally described in 1824 by American entomologist Thomas Say. The beetles were collected in the Rocky Mountains, where they were feeding on the buffalo bur, "Solanum rostratum". The genus "Leptinotarsa" is assigned to the chrysolmelid beetle tribe Doryphorini (in subfamily Chrysomelinae), which it shares with five other genera: "Doryphora", "Calligrapha", "Labidomera", "Proseicela", and "Zygogramma".