Besbicus maculosus

Quercus dumosa
Leaf galls, detachable
Fig 97. On under side. Outer layer peels off.

Fig 97. Q. dumosa and durata. Greenish, mottled with white when young. When mature a thin outer layer becomes loose. Adults were cut out Nov.22 (Hopland). One emerged Nov. 16 (Los Gatos).

Cynips maculosa, new species

Host -- Quercus dumosa

Gall (figs. 11 and 44). — Globular, 5-7 mm. in diameter, attached by a short stout stalk to the midrib on the underside of the leaf in the fall. Greenish, mottled with white while growing, turning brown as they mature, a very thin papery epidermal later becoming loosened and peeling off in fragments in old specimens. Inside is a darker stony-hard shell one-half millimeter in thickness, and within this a single larval cell supported by dense radiating fibers.

Habitat. — The type material was collected in Sequoia National Park, Calif., on September 9, 1922, between the western gate and the Cedar Creek checking station, on the Giant Forest Road. Some of the galls were still green and others turning brown. At that date they contained full-grown larvae, which pupated about October 1. The living flies were cut from the galls on November 10. The galls were also seen at Los Gatos and Lakeport and Ukiah. H. Morrison collected galls on Black Mountain, San Mateo County, in December, 1910, and reared an adult the next summer. Koebele collected galls in the Santa Cruz Mountains and others in Sonoma County.

Besbicus maculosus
*Cynips maculosus

This cynipid wasp induces monothalamous, pear-shaped galls attached to the ventral midrib of leaves of leather and scrub oaks.

Hosts:
Quercus durata
Quercus berberidifolia

Cynips maculosa
agamic forms

GALL. — Moderate sized, hard, spherical to flask-shaped leaf gall, up to 9.0 mm. in length and 7.0 mm. in greatest diameter. Regular, spherical to bulb-shaped, attached by a moderately stout, blunt tip which may be up to 1.0 mm. in diameter, evenly but rather abruptly enlarged into a swollen, ovoid body which is well rounded at the tip; essentially smooth and naked, but the epidermis thin, becoming papery, broken, and more or less dehiscent when mature and dry, making the gall appear ragged or (after the epidermis has dropped) leaving it very smooth and polished; the young galls greenish, mottled with white, becoming more yellowish, light orange, pinkish, or reddish brown, finally becoming light to dark brown or blackish. The outer wall of the gall of moderate thickness, hard, compact crystalline, somewhat brittle; the larval cell central in the swollen portion of the gall, at first small with a distinct cell wall, held in place by rather dense, irregular, tangled, crystalline fibers; the larval cell finally up to 3.0 mm. in length, then filling a large part of the gall, the fibers being then compressed into a more solid mass. Attached usually to the veins, on the under side of the leaf, sometimes on the upper side or on the petiole. On Quercus dumosa and Q. durata.

RANGE. — Known from Mendocino and Lake Counties southward in the mountains along the coast and in the Sierras as far as the Sequoia National Park. Figure 33.

The interesting gall of this species is apparently not rare in an area including Mendocino and Lake Counties, but there are no records for what is technically Southern California even tho one of the hosts, Q. dumosa , is one of the common oaks in that part of the state. The gall of maculosa is not to be confused with that of any other cynipid, but the insect very closely resembles Cynips mirabilis, differing chiefly in having a shorter fourth antennal segment, less heavily clouded patches on the wings, usually several spots in the discoidal cell, and a smaller size. It is instructive to compare the descriptions of the two insects and note how dependent we are on the physiologic measure (the gall) for separating them.

[Kinsey goes on to describe 2 varieties of the agamic gall of this species; see paper for details]