Sambucus (elder)
...
Tapered stem swelling...Neolasioptera pierrei (Gagné)
Swellings vary in size depending on the number of larvae within. Larvae overwinter in the stem, and adults emerge in spring. Host: S. canadensis. Distr.: Massachusetts and New York.
”- Raymond J. Gagne: (1989) The plant-feeding gall midges of North America©