Eurytoma obtusiventris
Eurytoma obtusiventris is a parasitoid of Eurosta solidaginis. It can be found in North America. The wasp attacks after oviposition but prior to the formation of a gall. Eurytoma obtusiventris prompts the Eurosta solidaginis larvae to create a pupa, which the wasp will use after consuming its host.  They typically consume the host in autumn and overwinter within the gall, emerging during the summer.

References

Hymenoptera of North America
Parasitic wasps
Insects described in 1934
Eurytomidae