Caryomyia striolata Gagne, new species

Hosts: Carya aquatica, cordiformis, glabra, ovata, tomentosa

Gall (Figs. 36-38): Common, a spring gall, on both Eucarya and Apocarya hickories; found singly or in groups on lower, rarely on upper, leaf surface, between or adjacent to veins; 3.5-5.0 mm in height, usually upright, sometimes leaning, base truncate, cylindrical, more or less fluted, tapering gradually to pointed apex; with sparse resin glands sometimes simulating hairs especially on young galls, white to green, occasionally with some red, turning brown; base of gall shallowly concave; wall uniformly thin, larval chamber rough with weak, longitudinal ridges. This gall is similar in shape to that of C. albipilosa, but lacks a thick covering of long white hair.

Affinities. — This species can be separated from C. albipilosa only by the lack of hair on the gall of this species and the thick coat of hair on the galls of C. albipilosa. See under the latter species for further discussion. [C albipilosa: Except for the presence of white hair covering the gall, I can detect no difference between this species and that of C. striolata. These are the only strictly spring-occurring galls in this genus. That the galls of these two species appear in spring and dehisce soon after further separates them from remaining Caryomyia spp.]

Biological notes. — Galls of this species and C. albipilosa are the earliest Caryomyia galls to appear in spring and grow to full size within a few days. Young galls are at first mostly green and soon develop some red tinge. While the host leaves were still flaccid in early May, galls were found already fully formed, all with similar mature shape and size, with each containing a first, second, or third instar. In other years, galls found on May 16-19 contained second and third instars and by May 23 most galls were hanging loosely on the leaves or had already dehisced as indicated by abscission scars. On May 28, galls remaining on the leaves contained dead or parasitized larvae. These galls eventually turned brown and did not dehisce because the gall ceased development upon the death of the larva and never completed an abscission layer. Any galls found on leaves after June 5 were brown and contained only dead or parasitized larvae. Such galls could be found through September.

Range: AL, CT, GA, KY, MD, NJ, DC, WV