Larva in achenes...Neolasioptera helianthi (Felt)

Infested achenes appear normal or slightly swollen. Larvae pupate inside and emerge through a hole in the crown....Heavily infested flower heads produce leaves in the center. Hosts: Helianthus spp. Distr.: widespread in North America.

Although N. helianthi was reared from H. strumosus, the specific site from which the type female issued is unknown...

Neolasioptera helianthi (sunflower seed midge) has the greatest host range and is the most abundant and
widely distributed cecidomyiid on sunflower. This was the only species that was common on Helianthus species in the western United States...

Larvae of N. helianthi develop in immature seed and leave pinholes in the crown of achenes when pupae extrude for adult emergence. In some instances, damage attributed to larvae of Smicronyx seed weevils in mature achenes may actually be caused by larvae of N. helianthi.

...reared from achenes of Helianthus strumosus...

[does not describe the galls, but earlier states that all Neolasioptera species in this paper form galls]