Caryomyia leviglobus Gagne, new species

Hosts: Carya tomentosa, ovata, texana, glabra, pallida

Gall (Figs. 19, 62-63): Common, on Eucarya hickories; single or dispersed on lower leaf surface between veins; 2.8-3.5 mm in height, spherical with a conspicuous apical terminus made up of a nipple atop an abruptly raised areola; hairless, not sticky, glabrous, light green, becoming yellow, green, or brown; base with small conical pedicel, leaf without exfoliation; wall firm, brittle, uniformly thin, larval chamber glabrous with longitudinal ridges. Wells (1916) wrote that the gall resembled a small bomb. This gall differs from that of C. spiniglobus in that it lacks hair. Both galls are distinctive for their conspicuous apical knob.

Affinities. — This species does not differ from C. spiniglobus except in the exterior of the gall that is smooth in C. leviglobus and stiff-haired in C. spiniglobus. I found galls of both species at the same site, but not in proximity on the same leaflet, so consider them separate species. While C. leviglobus is more common than C. spiniglobus, both are generally widespread. As with other species (viz. the C. caryae and C. cilidoliurn groups) that live unconstrained in a rather large, spherical larval chamber, the integument is completely covered with spiny verrucae that evidently allow these species purchase in crawling across the curved surface of the larval chamber.

Biological notes. — Tiny, soft, light green galls with first instars were first noted in central Maryland on June 10. After mid-June galls in various stages of hardening yielded all instars including thirds. Adults emerged from a slight bulge in the side of the gall that was evidently weakened by the larva the previous autumn.

Range: AL, AR, CT, FL, GA, KY, LA, MD, MA, MS, MO, NH, NY, NC, OH, OK, TN, TX, VA, DC, WV

- Raymond J. Gagne: (2008) The Gall Midges (Diptera: Cecidomyiidae) of Hickories (Juglandaceae: Carya)^©

Reference: https://www.biodiversitylibrary.org/page/38636615#page/60/mode/1up