Phylloxera deplanata Pergande, n. sp.

The galls of this species and their architects were carefully studied in 1883 on some small trees of Hicoria tomentosa growing on a hilly slope, bordering the Potomac River, opposite Georgetown, D. C. An interesting fact connected with the species was the absence of the winged or migratory generation, in which respect it agrees with Ph. c. -semen Walsh and PA. caryae-venae Fitch. That Ph. deplanata is distinct from this last is made patent by a comparison of the galls and stem-mother ; while it would also seem to be distinct from Ph. c. -semen, its western representative. The galls of Ph. c. -semen are the smallest known, measuring not more than 0.6-2 mm horizontally, being more or less subglobular and provided with a round orifice, surrounded by a fringe of 5-8 or more, rather broad bracts; whereas the galls of this species have a transverse diameter of 1-5 mm, are but slightly convex above and more prominent beneath ; the orifice is oval and without any bracts, but closely fringed with fine hairs. Its walls are rather thin and flexible, while those of Ph. c. -semen are thick and hard. In how far the insects of these two galls differ is not at present known, but there is little doubt that future more careful study of Walsh's species will reveal sufficient differences.

The leaves of some of the smaller trees are often literally covered with the galls of deplanata which then produce a sickly, yellowish and crumpled appearance thereof. By the end of June the galls are deserted, brown and dry, or else have completely decayed, leaving innumerable holes in the affected leaves, seriously affecting the health of the tree. When but a few days old (first week in May) these galls resemble minute yellow specks.

The transverse diameter of the mature galls varies from 1-5 mm; height about 1 mm; walls rather thin above and beneath and semi- transparent. Upper surface projecting but little above the plane of the leaf, convex, usually with a shallow fovea ; frequently not central and occasionally with a slight central elevation. Under side more strongly convex, sometimes almost conical, the nipple usually more or less flattened and generally leaning to one side, as if pressed down when young; with the orifice usually oval, though sometimes more or less rounded, and which before maturity is perfectly closed and densely fringed with short pale hairs. Color above either reddish with the depression yellowish, or almost entirely greenish -yellow ; below purplish or dull greenish-yellow. Many of the galls are conjoint, i. e., contain from 2-6 or more stem-mothers together with large numbers of eggs and sexual individuals, the cavity being completely crowded.

- Theo. Pergande: (1904) North American Phylloxerinae affecting hicoria (Carya) and other trees^©

Reference: https://www.biodiversitylibrary.org/item/114693#page/25/mode/1up