Tapered stem swellings observed on Artemisia vulgaris. Inducing organism is unknown. See listing on BugGuide here. Old galls have been observed in New York, New Jersey (2) (3), Pennsylvania, and Maryland.
Larvae of Mordellistena beetles have been found in these galls and reared to adults. These may be the inducer but are more likely inquilines. See paper by Abrahamson et al concerning similar inquilinism on galls of Eurosta solidaginis..
”- Gallformers Contributors: (2023) Gallformers ID Notes©