Neuroterus pacificus sp. nov.

Neuroterus batatus [partial synonym for galls in California on Quercus lobata]

The species described by David T. Fullaway as Neuroterus batatus Fitch from California on Quercus lobata is not this species and I propose for it the name Neuroterus pacificus. Dr. Isabel McCracken kindly sent me some of Fullaway's material as well as some collected by herself and Miss Dorothy B. Egbert. The galls occur on Quercus lobata, Q. kelloggi and Q. douglasi. The species is double brooded and the early summer galls are on the under sides of the leaves and the late summer galls are hard, woody swellings on the terminal twigs, containing numerous long, oval larval cells imbedded in the soft spongy interior of the gall.

Neuroterus quercus-batatus (Fitch)

Cynips quercus-batatus Fitch
Neuroterus batatus Mayr
Neuroterus quercus-batatus Dalla Torre & Kieffer

Gall. Early summer galls on under side of leaf of Quercus douglasi, a flat, irregular swelling, distorting the leaf, polythalamous, 8 mm by 5 mm, and a sordid brown color. Late summer galls, from which adult flies emerge the following spring, small hard woody swelling in terminal twigs of Q lobata, containing numerous long, oval larval cells imbedded in soft spongy interior of gall.

Habitat. Stevens Creek, beyond Cupertino CA. San Jose, CA.

Neuroterus cupulae Kinsey.

Quercus douglasii, dumosa, durata, garryana, lobata
Acorn galls
Fig 38. Cell in cup at base of acorn.

38. Q. lobata. Also on Q. douglasii, dumosa, durata and garryana. Adults were cut out March 1 (Boulevard).

Neuroterus quercicola var pacificus

We know of only one species of Neuroterus in the American continent galling acorns, Neuroterus cupulae Kinsey, 1922, later considered an asexual generation synonym of Neuroterus quercicola var. pacificus Kinsey (Kinsey, 1923; Weld, 1952), a species distributed in California.

Neuroterus cupulae, new species

On Quercus lobata.

GALL. — Only a larval cell buried in the wood of the acorn cup. The cell oval, averaging 1.5 mm. wide by 2.2 mm. long; the walls hard but not thick; entirely hollow. Buried wholly or in part in the wood of the acorn cup, oftenest at the base; part of the cell sometimes visible within the cup, only rarely producing a slight swelling on the outside of the cup.

Adults were emerging at Paso Robles on March 7, after most of the cupules had fallen to the ground. This is clearly an agamic generation, and very probably has an alternate, bisexual generation, probably not occurring on acorn cups. A similar gall occurs on Q. garryana on the north Pacific Coast; the insects will probably prove to belong to a distinct variety.

Range: CA, Paso Robles, Gilroy

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:

Acorn Galls: Single larval cells buried in the wood of the acorn cup. The cell oval, averaging 1.5 by 2.2 mm.; with moderately thin walls. Buried wholly or in part in the wood of the acorn cup, oftenest at the base; part of the cell sometimes visible within the cup, only rarely producing a slight swelling on the outside (fig. 57).

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.