Neuroterus varians Kinsey.

Quercus lobata
Stem galls, woody stem swellings or cells under bark
Fig 46. "Short, blunt, irregular stem swellings"

46. Q. lobata. Types emerged Mar. 21 (Byron). Emerging Apr. 24 (Newhall), May 5 (Santa Margarita).

Neuroterus varians, new species

Galls (Pl. XXIV, Figs. 17, 18). —Short, blunt, irregular stem swellings. Polythalamous. Distorted lateral stems, 5-12. mm in diameter, 6-35 mm. long, very rough, covered with bark of natural color; very irregular in shape; involving distorted buds, petioles or leaves. Internally the larval cells are closely compacted, located mostly at the periphery; cells oval, averaging 1.5 by 0.8 mm., but varying in size; cells with a distinct, shell-like lining which is not, however, separable. On Quercus lobata.

Range: —California: Byron.

This species shows a considerable variation in the size of the adults,the color of the legs, and the size of the areolet. All of the material, which gave almost eight hundred adults, was collected from a single tree; the smaller individuals appear structurally and almost entirely in regard to color indentical with the largest individuals, and what differences do exist show all the intermediate stages in still other individuals. So I have no doubt that these variations are all within a single species, but to avoid any chance of confusion I have sorted out a series of the largest individuals as paratypes.

Adults emerged March 21, a couple of days after collecting the galls.

Neuroterus quercicola variety pacificus
agamic form varians Kinsey

Neuroterus quercus-batatus (woody gall only)
Neuroterus pacificus (woody gall only)
Neuroterus varians
Neuroterus cupulae

GALL. — A slight swelling of the affected part, the larval cells with a distinct but inseparable lining; galls of two types as follows:

Stem Galls: Short, blunt, irregular swellings; up to 35. mm. in length, and 12. mm. in diameter; very rough, covered with bark of normal color, also involving distorted buds, petioles, or leaves; some- times not producing much of any swelling. Internally filled with closely compacted, oval larval cells, located mostly toward the periphery (figs. 51,55).

Adults emerged from twig galls at Byron on March 21, 1920, a couple of days after collecting, and from both twig and acorn galls on March 7, 1920, at Paso Robles. The twig galls which Fullaway had, bred adults on February 15 in the laboratory. All of the insects had previously emerged from twig galls I collected on March 3, 1920, at Zelzah, and March 23 at Three Rivers. Emergence, then, occurs early in the spring before the buds have opened, and it is in these closed buds that the insect oviposits to produce the flower stem, and leaf vein galls of form pacificus.

There can be no question of the identity of varians and cupulae. I described these as distinct species primarily because the galls of the two are so very different that the possibility of their identity never was entertained. I never compared the two descriptions, and only a revision of the whole genus, analyses of subgenera, and the writing of comparative descriptions, Anally showed me the mistake. This is an indictment of the publication of miscellaneous new species, and justification of the revision of whole groups at a time. Varians and cupulae are synonyms, not because the insects largely resemble each other, but because detailed examination of large series of the types of the two fails to disclose a single point of constant, group difference. Insects were emerging from both kinds of galls at the same date from the same trees at Paso Robles in 1920.

Here is one of the most remarkable cases known of one cynipid producing two or more distinct kinds of galls on different parts of the host. Several other cases are pointed out in this paper for the genus, but otherwise few cases of gall polymorphism are known in the Cynipidae. Varians lives either in twigs or acorn cups. In the first instance the galls are polythalamous swellings packed with larval cells, while in the second instance they are single, scattered larval cells which produce almost no swelling. So does the plant tissue determine the character of the gall! It might be suggested that the two insects, altho alike morphologically, are different physiologically as evidenced by their different points of oviposition, but such matters cannot be investigated with our present means. Meanwhile it appears probable that insects from either type of agamic gall lay eggs for either type of bisexual gall, apparently due to the lack of a peculiar physiology which might restrict oviposition to a single point on the plant.

Range: CA, thruout central CA and possibly wherever Quercus douglasii and lobata occur.