Zapatella quercusphellos

(Osten Sacken) comb. n.

Cynips quercusphellos Osten Sacken, 1861. Callirhytis quercusphellos (Osten Sacken ) (Burks 1979).

Cynips quercussimilis Bassett, 1864, syn. n. Callirhytis quercussimilis (Bassett) (Burks 1979).

Callirhytis (Cynips) quercussimilis (sexual form) was known, inducing stem swelling galls on Quercus incana, Quercus falcata, Quercus ilicifolia Wangenh., Quercus imbricaria Michx., and Quercus myrtifolia along the Atlantic coast, from Florida to New York state (Burks 1979). The galls are club-shaped swellings if they form on terminal twigs, with 1–4 cells (Weld 1959). Green and fleshy galls develop in May, and later turn woody (become lignified). Adults emerge in June to the beginning of July (Bassett 1864, Weld 1959).

The author of Callirhytis quercusphellos (Osten Sacken 1861) collected greenish rounded woody swellings at the tip of the twigs of Quercus phellos (L.) in Virginia, near Potomac river in June; four sexual females emerged by the end of June Osten Sacken (1865) mentioned that his species somehow resembles Callirhytis quercussimilis (Bassett), however, differs from it. Dalla Torre and Kieffer (1910) treated them as different species. Weld (1922b) erroneously synonymised Cynips similis Bassett to Callirhytis quercusphellos (O.S.). Later, the two species were treated as different species (Weld 1926, 1928, 1951, 1959; Burks 1979). Weld (1922b) observed galls absolutely similar to those of Zapatella quercusphellos on Quercus falcata, Quercus incana, Quercus texana Buckley, Quercus laurifolia Michx. and Quercus myrtifolia.

Zapatella quercusphellos was collected also at Rosslyn, Virginia from Quercus imbricaria in June and Quercus phellos in May, adults emerged in late June. In both cases the greenish fresh galls were similar terminal enlargements on new growths, inconspicuous, only 5 mm long; after maturation galls were 8–10 mm in diameter (Weld 1926).

A detail examination of specimens of Callirhytis quercusphellos and Callirhytis quercussimilis, mentioned above, showed no appreciable morphological differences and thus, Callirhytis quercussimilis is a syn. n. of Callirhytis quercusphellos and here in the species transferred to the Zapatella genus, Zapatella quercusphellos, comb. n.

Only the sexual generation is known. It induces stem swelling galls on Quercus incana, Quercus falcata, Quercus ilicifolia Wangenh., Quercus imbricaria, Quercus myrtifolia and Quercus phellos along the Atlantic coast, from Florida to New York state (Burks 1979).

Category: Monothalamous terminal enlargements or club-galls of twigs

Callirhytis similis Bass. 1864. p 683. (Cynips) Q. ilicifolia, Conn; Harvard Coll, NY; Beut. Cat., Q. nana [ilicifolia], Q ilicifolia, NJ; Q ilicifolia, Q stellata [presumably an error?], Mass, RI.

Description: Terminal or not terminal.

Callirhytis similis (Bass.)

Quercus falcata, ilicifolia, imbricaria, myrtifolia, texana [buckleyi]
Stem galls, woody stem swellings
Woody, club-shaped when terminal, with 1-5 cells. June. Described from Quercus ilicifolia.

[Photo caption] On Q ilicifolia. Also on imbricaria, falcata, cinerea [incana], myrtifolia. Green and fleshy in May, becoming woody later. Adults emerged June 26, 28, 30, and July 3 (DC).

Callirhytis phellos (Ashm.)

Quercus imbricaria
Terminal on new shoots in spring, the larval cell supported by inconspicuous fibers.

Quercus laurifolia, phellos
Club-shaped at end of new shoots in spring with radiating fibers about the larval cell. 3-5 mm in dia.

[Photo caption] On Q. phellos. Also on Q imbricaria. Terminal on new growth. Maker emerges in late June (DC).

Cynips quercus similis n. sp.

QUERCUS ILICIFOLIA. Club-shaped, woody galls, growing on the ends of the small limbs. Apex blunt and generally turned to one side, covered in summer with a few leaves and containing one, and occasionally two or three larvae. It is strikingly like that of C. q. tuber of Fitch, but produces a fly which though closely related, is evidently a different species.

Callirhytis quercusphellos (Osten Sacken 1861)

Hosts: Quercus inopina, myrtifolia

[Asexual generation stem swelling gall found in Florida in the spring.]

Callirhytis quercussimilis (Bassett 1864)

Hosts: Quercus inopina, myrtifolia

[Sexual generation stem swelling gall found in Florida in the spring.]