Caryomyia caryae (Osten Sacken)

Diplosis caryae Osten Sacken 1862: 191; Felt 1909:293 (Caryomyia).
Hormomyia arcuaria Felt 1908: 388; Felt 1918: 46 (Caryomyia). New synonym.

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

Gall (Figs. 18, 20-20a, 55-58): Common, found on Eucarya hickories; single or clustered, on lower leaf surface, usually between veins but may occur on vein; 2.5-3.5 mm in height, spheroidal, sometimes bulging out to one side at midlength, apex with short umbo, less often gall subcylindrical and constricted near basal third; green or yellow, becoming tan to red or brown, hairless, more or less sticky, variably covered with small resin glands; base with weak to prominent conical pedicel in center of circular indentation, leaf in most specimens slightly exfoliate surrounding base of gall, in subcylindrical form more conspicuously so; wall firm, brittle, of uniform thickness, usually thin, larval chamber shaped as for gall, yellow, brown, or purple, glabrous, with longitudinal ridges. This gall is generally similar to that of C. shmoo, but the gall of the latter is conspicuously narrow at its apical third, while the present gall is more evenly spheroidal.

Affinities. — As mentioned in the gall description, two intergrading kinds of galls are formed by C. caryae as defined here (compare Figs. 55-56 with 57-58). This species is apparently related to C. hirtiglobus and C. shmoo because of the general conformation of the gall with its acute-conical connection to the leaf.

Biological notes. — In central Maryland, galls were first noticed in late May when they contained first and second instars, but the galls were immature, soft and very sticky. Small, barely noticeable adjacent galls with first instars were recognizable but smaller and stickier. Through the first week of August most galls are brittle and contain second instars, but during this period occasional galls may contain a third instar. After early August galls usually contain third instars. Adults were reared in early April the following year.

Range: AL, AR, CT, FL, GA, IL, KY, LA, MD, MA, MS, MO, NH, NY, NC, OH, OK, Ontario, PA, SC, TN, Tamaulipas, 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/34/mode/1up