Actually
It is illegal to keep / breed D. couperi within Alabama, Florida, Georgia, Kentucky, Mississippi, New Jersey, New York, South Carolina and Virginia without special state level permits. You will also be required to obtain a USF&W interstate commerce permit prior to obtaining a D. couperi from a source outside of your own state of residency.
As for D. m erebennus, the species is granted protection by the state of Texas only, so no permits are required for such unless you reside within the "Lone Star" state, in which case, you would be required to obtain a permit to keep D. m erebennus from the state of Texas, which are close to impossible for an individual hobbyist to obtain. Also, there has been some discussion regarding the legality of keeping any Drymarchon spp. in Texas, as it has been mentioend that the regulations protect D. m erebennus at the genus level, not just the species and sub-species level, which technically means, all members of the Dry clan would be off limits to those residing within Texas...
Best of luck to you,
Jeff