Caryomyia persicoides (Osten Sacken)

Cecidomyia persicoides Osten Sacken 1862: 193; Felt 1918: 46 (Caryomyia).

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

Gall (Figs. 17, 126-129): Common, found on Eucarya hickories; single or clustered, on veins of lower leaf surface; 5.1-9.0 mm in height, spheroidal or conical, base flat against leaf surface, clasping leaf vein, edge around base acute and lobed to obtusely rounded, tissue on apical third eventually collapsing somewhat and becoming furrowed when mature; covered with short, dense, velvety, green, yellow, tan, or red hair obscuring surface; connection to leaf circular and shallowly concave or flush with leaf; larval chamber located basally, ovoid, lined with yellowish pellicle different in texture from surrounding soft, spongy, green to purple, viscous tissue that partially collapses with age; a bundle of fibers present between apex of larval chamber and gall apex. Galls may be gum-drop shaped to nearly spherical. The uniform covering of dense, short hair is only slightly longer in galls of C. spherica, but the latter galls are always spherical, hard and woody, and the larval chamber is located at the very center of the gall.

Affinities. — Galls somewhat resemble those of the C. sanguinolenta species group because of their extensive soft tissue and the presence of a pellicle lining the larval chamber. A large difference between their galls is that only the top section of C. persicoides and C. turbanella galls breaks off over the winter as a unit, while all the soft tissue on the top and sides of the galls of the C. sanguinolenta group eventually separates from the brittle pellicle. Also, pupae of C. persicoides and C. turbanella break out of the side of the gall, while those of the C. sanguinolenta group break out of the bottom of the larval chamber. In addition to these differences, adults of the two groups are different enough that it appears soft-tissued galls evolved at least twice in Caryomyia.

Biological notes. — Galls of this species seem to be more commonly found in late summer. In central Maryland I occasionally found small galls with first instars beginning in mid-June but the galls seemed more numerous beginning in early August, when I found galls with larvae in first or second instars. Third instars were apparent in late August and September. Pupae break through the side of the gall. I once noticed a sciarid pupal exuviae sticking out of a hole near the gall's apex; possibly some other organism made the hole.

Range: AL, AR, CT, FL, GA, IL, IN, KY, MD, MA, MO, NH, NY, NC, OH, OK, Ontario, PA, SC, 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/64/mode/1up