Unidentified blue green bug/beetle

Unidentified blue green bug/beetle

Observation - Unidentified blue green bug/beetle. Description: Found thousands (probably millions) of these flying beetles or bugs in a corn field near our home. Blue Green body with an orange/brown neck and two antennae at front - about 5mm long. Thought they were cereal leaf beetles which are 'Oulema melanopus' but

Found thousands (probably millions) of these flying beetles or bugs in a corn field near our home. Blue Green body with an orange/brown neck and two antennae at front - about 5mm long. Thought they were cereal leaf beetles which are 'Oulema melanopus' but the internet pictures seem to be different so I now think I agree with rockwolf that it is more likely 'Gastrophysa polygoni' which is also a type of leaf beetle - but is different sub-family of the Chrysomelidae family - cannot find anything else to match it.