Andricus crenatus Weld.

Quercus douglasii, dumosa, engelmanni
Leaf galls, detachable
Fig 136. Saucer-shaped disk, 4-5 mm, under side.

Fig 136. On Q. dumosa, douglasii, engelmanii. They mature in August. Adults emerged Nov 10 (Colfax), Nov. 22 (Stanford) emerged and died by Dec. 15 (Los Gatos).

Andricus crenatus, n. sp.

Host. — Quercus dumosa and Q. douglasii.

Gall (pl, 17, fig, 18). — A spangle about 4 mm. in diameter, usually on the upper side of the leaf, saucer shaped, with a thin crenate margin when young in August and with a prominent hump in center, Wlien mature in fall there is a lens-shaped larval cavity inside, on the floor of which is a thin, white, circular disk from which prominent lines radiate. Galls on Quercus douglasii are less crenate.

Habitat. — The type is from a series of dead adults cut out of galls collected on Quercus dumosa at Los Gatos, Calif,, on December 13, 1935. Others, all from California, are from the San Bernardino Mountains, San Jacinto Mountains, and Banning; other paratypes emerged November 19, 1935, from galls collected at Colfax, on Quercus douglasii a few days previously ; others are from Stanford University and Angels Camp. Similar galls have been seen on Quercvs engelmanni at Santa Anita, Calif. Adults not included in the type series have been reared from galls on Quercus garryana at Siskiyou summit north of Holbrook, Calif.

Andricus gigas (unisexual generation)

The saucer-like unisexual-generation galls are narrowly attached at the base and have thin, flaring edges that are either smooth or toothed (crenate).

Hosts:
Quercus douglasii
Quercus berberidifolia
Quercus engelmannii

Feron gigas (Kinsey, 1922), comb. nov.

Galls. Asexual spangle galls (Fig. 215) about 4 mm in diameter, usually on the upper side of the leaf, saucer shaped, with a thin crenate margin when young, with a prominent hump in center. The mature gall has a lens-shaped larval cavity inside, on the floor of which is a thin, white, circular disk with radiating prominent lines.

Biology. Alternation of sexual and asexual generations was determined by Dailey & Sprenger (1973a). Alternate sexual and asexual generations are also confirmed herein using DNA data, with four individuals (three asexual females, one sexual male) sequenced for cytb and three individuals (two asexual females, one sexual male) sequenced for cytb. Cytb sequences were on average 0.82% divergent (range 0–1.66%; GenBank accessions KX683598, OQ446198–OQ446199) and ITS2 sequences were identical among the three individuals except for two additional bases within a polyA region in one sample (GenBank accessions OQ448240–OQ448242).

This species induces galls on Q. douglasii and Q. dumosa (section Quercus, subsection Dumosae). Young asexual galls are present in August, mature in autumn; asexual adults emerge in February. Sexual galls are mature in April; adults emerge by the end of April.

Distribution. USA: California.

Andricus gigas

Field observations and rearings have shown the bisexual generation of Andricus crenatus Weld (1952) is Andricus gigas Kinsey (1922). Because Kinsey erroneously described a toothed tarsal condition, Weld (1951) transferred A. gigas to Dryocosmus Giraud. Due to the actual toothed tarsal claws of both generations, the species is now returned to the original placement in Andricus Hartig. The valid name again becomes Andricus gigas.

Host:
Quercus douglasii