Complex sentence: The body presents a wasp-like structure, but with several ant-like characteristics, which are primitive compared to more modern ants, thus it is intermediate with other primitive ants and aculeate wasps.
Split into simpler sentences: The body presents a wasp-like structure but with several ant-like characteristics. These ant-like characteristics, however, are primitive compared to more modern ants, and thus it is intermediate with other primitive ants and aculeate wasps.