HealthSpring — acquired by Cigna earlier this year — is taking over some Aetna operations in Texas and Arkansas.

Cigna (NYSE: CI) officials announced late Wednesday an agreement with Humana to purchase select Medicare Advantage plans in Texas and Arkansas. The plans are located in Amarillo and Longview-Marshall, Texas, and Texarkana, Ark., and have 3,500 members combined. All are part of the government-stipulated divestiture for Humana to complete its March acquisition of Arcadian Health.

“We welcome our new customers to our talented team of doctors and staff that have proudly served our customers for over a decade,” HealthSpring President Herb Fritch (pictured) said in a presser. “At HealthSpring, we dedicate significant resources to meet the individual needs of each and every one of our customers and we look forward to delivering our service to more Texas and Arkansas seniors.”

HealthSpring expects to extend its service area for the first time to Arkansas seniors in eight counties, officials said. In Texas, HealthSpring currently offers coverage in 49 counties and will add 10 new counties from this agreement. Membership in two other existing HealthSpring Texas counties are also part of the agreement.

The transaction is expected to close at the end of 2012 following customary regulatory approval.