Agamic gen. of Neuroterus batatus (Fitch)

Stem galls.
In winter a similar [to N batatus sex gen] but woody gall covered with normal brown bark, the adults emerging the latter half of April and ovipositing in the buds.

Neuroterus quercus-batatus (Fitch)

Quercus alba
Stem galls, woody stem swellings
Agamic. Woody, covered with normal brown bark, persisting over winter.

[Photo caption]
Fig 125. On Q. alba. The woody gall persists over winter. Adults emerge Apr 16-26 (IL); May 6 (DC).

[Presumed synonyms]
Fig 126. Never reared. Woody stem swelling on Q chapmani. Resembles the woody form of Neuroterus quercus-batatus (Fitch).

Neuroterus quercusbatatus (Fitch)

Cynips Quercus-batatus Fitch 1859: 810. Females and males (type examined).
Neuroterus batata Basset: Ashmead 1885a: 296, 303.
Neuroterus quercusbatatus: Burks 1979: 1074.
Cynips noxiosus Bassett 1881: 108. Females, males, galls of both generations (types examined). New synonymy.

Distribution.-Ontario, Rhode Island, Connecticut west to Illinois, Colorado, south to Florida.

Biology.-Alternate bisexual and unisexual generations are known. Both generations induce stem-swelling galls on Quercus alba L. (Ashmead 1885a, Burks 1979). The gall is a woody, elongate stem swelling. It is polythalamous, with an irregular shape and a surface that is covered by normal bark, twisted, but in large part cylindrical, tapering gradually to the stem at both ends and up to 60 mm long by 20 mm wide in the unisexual form. Sometimes several galls can more or less fuse, drying brown in bisexual forms, or with a whitish or purplish bloom in unisexual forms [an apparent mistake, copied from Kinsey; these should the other way around]. Internally hard and woody, the tissue is little modified except by the larval cells which are densely packed, each with a distinct but wholly inseparable lining. The unisexual form develops on young stems, involving petioles and leaf midveins. The unisexual form begins to develop in mid-summer, forming woody stem galls. The adults overwinter in the galls and emerge in spring after the oaks are actively growing.

C. q. batatus Fitch.

Quercus alba.

I am satisfied that there are annually two generations of C. q. batatus. The first appears early in May, from galls of the preceding year's growth,--the last late in June, from green galls. I have often found perfect insects in the galls in winter, and have reared flies from them, apparently of the same species reared from the summer galls. Inquilinae in great numbers are produced from the winter galls and few true gall flies, while the reverse is true of the summer form. As many of the summer galls remain green after the flies have left them, and as the tree's annual growth is nearly or quite complete the first of July, it seems probable the June flies oviposit in the galls from which they were produced.

Neuroterus batatus (Fitch)

The woody winter form of the "oak potato gall" on the stems of Quercus alba has been noted [in IL, IN, FL, DC, MA]. In the Chicago area the agamic females issued April 15-24, 1910, and were observed to oviposit in buds at end of the same twig in breeding jar. In 1913 they emerged April 20-26. At DC they were emerging March 14, 1921.

Neuroterus batatus form batatus

Galls. — Large, woody, stem swellings (Figs. 10 to 12). Polythalamous. Averaging 40X10 mm., often larger; tuber-like, irregular, but usually roughly cylindrical, elongate, involving stems and bases of petioles on terminal twigs; inseparable from the rest of the plant. Bark-colored, reddish, purplish brown, or with a glaucous bloom. Internally the galls are solid, woody, the larval cells scattered irregularly, the cell walls hardly distinct and not at all separable from the surrounding tissues. On terminal stems of Quercus alba (not known definitely from any other species of oak).

Range: Canada. NH, MA, RI, CT, NY, NJ, VA, OH, IL, MI, CO

The galls of this generation, because they remain upon the tree for the longer time and often reach the larger size, are the better-known of the two forms of this species. The insects live in the galls over winter, emerging late the following April or early in May. The very great similarity of the adults of the two generations of this species (except for the agamy in the winter generation) and the essentially identical plan of the galls of the two forms, is a matter of great interest. In this species, as in Neuroterus noxiosus, we find as simple a case of alternation of generations as has yet been recognized. The differences in the galls are very evidently due to seasonal differences of the conditions in the part of the host affected.

Neuroterus batatus Fitch
Agamic form, batatus Fitch

Gall, tuber-like, irregular, polythalamous stem swellings.

Adults, April, May

On Q alba

Neuroterus batatus var. prini Kins.
Agamic form, deprini Kins

Gall as described for agamic forms on Q prinus [montana]

Adults, April