[S. canadensis-type]:
"5- to 15-mm diam. when larvae mature, nonmarginal galls round to elliptical, but marginal galls lunate…Color variable: yellow, gray, buff, or purple with a pink center and ringed with white. Strikingly different-colored galls sometimes appear on the same leaf. Circular galls usually contain more than 1 larva but marginal galls typically contain only 1."

[S. juncea-type]:
"circular, about 3-4 mm diam. with only 1 larva/gall. Color dark gray with white or yellow margin becoming dull black or brownish when larva is mature."

[He lists the following host records for this species, verified by both host and insect identification: Solidago angusta [S. petiolaris var. angusta], S. arguta, S. caesia, S. californica, S. canadensis [S. canadensis, S. altissima, and presumably other very close relatives], S. chadonnetii [S. rigidiuscula], S. concinna [S. missouriensis var. extraria], S. confinis, S. curtisii, S. delicatula, S. dumetorum [S. gigantea?], S. elliotii [S. latissimifolia], S. erecta, S. fistulosa, S. gigantea, S. juncea, S. missouriensis [S. missouriensis var. missouriensis], S. mollis, S. nemoralis, S. rigida, S. rugosa, S. sempervirens [S. mexicana, based on location], S. sparsiflora [S. velutina], S. speciosa [S. rigidiuscula], S. squarrosa]

- Raymond J. Gagné: (1968) A Taxonomic Revision of the Genus Asteromyia (Diptera: Cecidomyiidae)^©