Callirhytis batatoides

Quercus virginiana, geminata
Stem galls, woody stem swellings
Abrupt swellings of twigs varying in form and size, many celled.

[Photo caption]
On Q virginiana. Also on Q geminata, fusiformis. Adults out in Feb, Mar, Apr 25-May 1 (FL).

Cynips q. batatoides n.sp.

Abrupt, potato-like swellings of the twigs and branches, varying in size and form, from 04. to 0.7 and sometimes an inch long, and 0.3 to half an inch or more broad; the outer surface is rough of the same color as the bark; internally it is white and in consistency not unlike a potato. No kernels; each insect separated by a very thin, hardly perceptible parchment-like substance. In on of the galls I counted fifteen gall-flies.

Plagiotrichus batatoides

GALL. — Quite similar to the galls of the other agamic forms of the genus; generally large, robust, up to 20. mm. in diameter and 28. mm. long; usually more irregular, composed of rather distinct, rounded parts, more or less fused; internally inclined to become partly hollow, the larval cells closely embedded, not very distinctly lined. On twigs of Quercus virginiana.

RANGE. — Florida, Georgia, and possibly elsewhere. The typical variety confined to an area including Jacksonville, Florida.

At this time I can add little to our knowledge of this species because I do not have insects enough to determine how many varieties it may have, and the range and hosts of each. The above descriptions, made from types, will separate this species from others of the genus, and give further details probably characteristic of only the typical variety. I have galls from a number of localities in Florida and Georgia, rep- resenting certainly more than one variety. Moreover some of the galls are from Quercus virginiana, some from Q. laurifolia, and some from Q. stellata. Probably each host has a distinct form for each faunal area. The Q. stellata galls from Georgia may represent a variety of Plagiotrichus elongatus, altho the galls are more like batatoides galls. Dozier states that galls collected early in December gave adults late in January; Weld bred adults on April 12, 1914. All of my galls were collected early in November, and I failed to secure adults probably because the larvae were still too young when the galls were dried. These galls are pecked into by birds and gnawed by mice, as Ashmead also recorded with the original description. Older galls persist on the trees until many of the live oaks are thickly covered with them. They are the favorite abode of ants which tunnel the soft tissue, further its early decomposition, and establish their colonies inside. Many of the old galls are almost hollow, covered by mostly complete bark, but internally a mass of thinly separated tunnels and decomposing chewings. The insect shows very distinct relationships to the other white oak species of the genus, rather than to the black oak species, but in many respects it is the most unique of the white oak species. The discovery of other varieties may link it more directly with some other species. Plagiotrichus elongatus rufopleurae, occurring in Texas on Quercus breviloba, is in some respects similar to batatoides, but more closely related to the other varieties of elongatus.

Callirhytis quercusbatatoides (Ashmead 1881)

Hosts: Quercus geminata, minima

[Asexual generation stem swelling galls found in the fall]