Diplolepis operta, new species

Host. — Quercus lobata.

Gall. — A seed-like cell hidden under the bud scales as in the case of the preceding species but broadest at the base and tapering gradually to a conical and much more pointed apex which lacks a scar. It has a smoother tan-colored surface and a much thinner wall (.05 mm). Length 2.8 mm. by 1.2 mm. in diameter near base, reaching much nearer to the apex of the bud than the preceding. Exit hole .9 mm. in diameter, in side of bud. One or rarely two in a bud.

Habitat. — Cottonwood, Calif. Reared in January and early February

Andricus opertus
Agamic generation

[Photos of this gall appear on page 4 of the pdf]

Callirhytis nigra
Diplolepis operta
Andricus nigridius
Andricus opertus

GALL (Figs. 3, 4). Usually completely concealed within the leaf buds, eccentric, occasionally causing minor distortion. Approximately 2.5 mm long, shape varying from flattened-ovoid to pointed-ellipsoid. The pale brown shell of the mature gall is polished and sparsely striate longitudinally. There is usually only one gall in a bud. It may be distinguished from the somewhat similar gall of Disholcaspis eldoradensis (Beutenmueller) by its earlier occurrence, smaller size and stubbier shape, generally darker color, and more striate appearance.

Range: northern CA

Agamic females chew relatively large circular exit holes subapically on the gall and through the side of the bud during late March to mid-April. They oviposit in the opening leaf buds.

Callirhytis nigra n. sp.

Gall. An irregular swelling or enlargement of the terminal twigs [apparently mistaken, see other sources] of Quercus lobata, subglobular, 15 mm. x 12 mm., apparently monothalamous.

Andricus nigridius, new name

Callirhytis nigra
Diplolepis operta
NOT Andricus luteicornis var niger
NOT Andricus niger

C. nigra was described as from a twig swelling on Quercus lobata and being thought to have simple claws was placed in Callirhytis. The unique type at Stanford University examined in 1935 has the claws toothed and was found to agree with paratypes of Diplolepis operta Weld, which came from galls inside the buds of Q. lobata. The type gall at Stanford is a twig swelling, which also bears a large bud with an exit hole in the side, and the type fly evidently came from a gall inside the bud rather than from the twig swelling. As the name niger was preoccupied in Andricus by Tavares in 1902, the new name nigridius is here proposed for nigra Fullaway,