Leaf, under side, arising from a shallow cup-like structure. Shape of
a slender horn, slightly curved, 5-7 mm. long, 1¼ mm. wide at base.
Light green at base, changing to yellow, the distal ⅔ of the gall a
deep brown. No demonstrable opening at the end. Walls thin. Surface
smooth, under lens minute longitudinal striations evident. Very little
discoloration on the upper side of the leaf to mark the location of the
gall beneath. Resembles _Caryomyia tubicola_ O. S. but is certainly a
different species.
Collected in Hocking County, Ohio, July, on _H. alba_.
Type specimens at Ohio State University.