Atrusca clavuloides

Club Gall Wasp

Antron clavula

 Cynips clavula

Dryophanta clavula

Cynips teres var. clavuloides

Diplolepis clavula

Cynipidae

Xanthoteras

Quercus lobata

California

Nevada

Cynipid Galls of the Pacific Slope

The Gall Wasp Genus Cynips

Xanthoteras clavuloides (agamic)

Dryophanta clavula, sp. nov.

Gall. — On the under side of the leaves of a species of white oak (probably Quercus douglasi). Monothalamous. Narrow and almost parallel to about the middle, thence suddenly becoming inflated into a club with the apex pointed. At the extreme base it is slightly broader and is attached by a point to the leaf. The gall very much resembles a miniature Indian club in shape. Brown in color, and the larva lives in the inflated part of the gall in a rounded cell. Length, 5-7 mm. ; width of narrow part, 1 mm., of thickened part, 1.75 mm. 

Habitat: — California (Napa and Sonoma Countries). Described from twelve specimens.

Descriptions of New Species of Cynipidae

Diplolepis clavula (Beutenmuller)

This species was described from a series of flies in the National Museum reared from galls collected by Koebele in Sonoma and Napa Counties. The writer collected galls on Quercus lobata at following locations in California: Chico, Calistoga, Stockton, Kaweah, and Lebec. Dr. J. C. Bradley collected one at Napa. The galls are just starting in August and become full grown in September and should be collected in late fall for rearing. 

Field notes on gall-inhabiting cynipid wasps with descriptions of new species

Cynips teres variety clavuloides, new name
agamic form

Dryophanta clavula
Diplolepis clavula

GALLS. — Slender, long, up to 8.0 mm. in length, the stalk nearly twice the length of the swollen portion of the gall, the swollen portion slender to broad spindle-shaped, drawn out into a slender point apically; on leaves of Quercus lobata. Figures 142-143. 

RANGE. — California: Yorkville and Clear Lake (galls, Leach in Kinsey coll.). Kelseyville (P. Schulthess in Kinsey coll.). Sonoma and Napa Counties (types; Koebele coll.). Napa (galls, Leach in Kinsey coll.; also J. C. Bradley acc. Weld 1926). Sacramento (in Mus. Comp. Zook). Chico, Calistoga, Stockton, Kaweah, and Levee (galls, acc. Weld 1926). Concord (C. T. Dobbs in Kinsey coll.). Mt. Diablo (Leach in Kinsey coll.). Palo Alto (Wiltz in Stanf. Univ.). Sierra foothills east of Dinuba, and St. Johns River near Klink (L. H. Powell in Kinsey coll.). Confined perhaps to a narrow area rimming the Central Valleys of California, probably limited to Q. lobata. Figure 28. 

This distinctive gall is never abundant, but it is usually included in collections made in the autumn on the Valley white oak of the foothills rimming the Central Valleys of California. The young galls begin development in August (acc. Weld), and are fully grown by the middle of September (September 12 in 1921 at Concord). Galls collected as early as October 4 (in 1925 at Kelseyville) had very large larvae in them. Most of the insects 1 have bred have emerged during the first half of January, but the Kelseyville material emerged between January 29 and February 5, 1926. McCracken and Egbert record January emergence for indoor breeding. 

All of the material I have examined has come from Q. lobata , and if this or a related variety ever occurs on Q. Douglasii it would appear to be rare. In the original description Beutenmiiller’s host record ran “a species of white oak (prob- ably Quercus douglasi).” He corrected this to “Quercus lobata ” in his subsequent treatment of the genus Dryophanta. I do not know the basis of the McCracken and Egbert record for Q. Douglasii. 

While we may yet find this variety in the Central Valley proper, it is noteworthy that up to date the only records are from the foothills rimming the Valleys from their northern to their southern limits, a peculiarly outlined area that has other insects and plants confined to it. 

The figure in Kellogg’s American Insects, and galls in my collection taken east of Dinuba, show larger, more swollen apices than any of the galls from other parts of California. The insects from the Dinuba material similarly average larger. 

Upon transferring this insect to the genus Cynips , Beutenmuller’s name of clavula, being preoccupied, gives way to teres for the species and a new name for the variety. 

There are galls of this species in the Ashmead collection at the National Museum labelled types of Andricus claviger Ashmead. This is a confusion of material, for the holotype insect of claviger represents a Florida species of an entirely different genus. 

Antron clavula (Beut.). 1911 Ent. News 22:67. 9 O. (= clavuloides Kinsey). Sonoma Co., Calif. 

Quercus lobata 
Leaf galls, detachable
Fig 106. Erect club on vein on under side. Fall.

Fig 106. Q. lobata. Galls develop in August. They are collected in December on fallen leaves. Adults have been cut out on Dec. 21 and Feb. 9 (Stanford).


Xanthoteras clavuloides, new combination

Cynips clavula (preoccupied)
Dryophanta clavula
Cynips teres var. clavuloides (new name for Cynips clavula)

Weld (1951) placed this unisexual species in Antron, but because clavuloides has a malar groove, it keys to the bisexual generation of Xanthoteras in Weld’s (1957) generic key to western U.S. cynipids. The absence of a malar groove in Antron is a major separation feature from Xanthoteras in this key, at least for the bisexual generation. Weld obviously recognized the proper generic assignment of clavuloides because it is in his unpublished ms. key to the species of Xanthoteras (under the name clavula). 

The separation of Xanthoteras from Antron on the basis of the malar groove may work for the bisexual generation, but it is not entirely satisfactory for unisexual forms. Xanthoteras teres Weld, a unisexual, micropter- ous species, does not have a malar groove, but it seems closely related to X. clavuloides, a macropterous species, on the basis of a bristly ventral abdominal spine, and similar brown, club-shaped galls. Clearly the generic limits of Antron and Xanthoteras are in need of study. 

Although homonymy between Beutenmuller’s and Osten Sacken’s species no longer exists, Kinsey’s name clavuloides must be used under the provisions of Art. 59 of the Code. Beutenmuller described clavula from galls and “twelve specimens from Napa and Sonoma Counties.” There are 59 adults in the USNM labeled Sonoma Co., 11 of which bear “type” or “cotype” labels. We have chosen the best of the “type” specimens as the lectotype. There is no material labeled Napa County. 

Nomenclatorial notes on North American Cynipidae (Hymenoptera)

Xanthoteras clavuloides

This cynipid wasp induces detachable, monothalamous, hairy, club-shaped leaf galls on valley oak. 

Host:
Quercus lobata

Plant Galls of the Western United States

An apparently inquiline-modified gall of this species was observed on Quercus lobata in California in [December](https://www.inaturalist.org/observations/66503384). Another gall that may also be an inquiline-modified gall of this species was observed on Quercus lobata in CA in [September](https://www.inaturalist.org/observations/96723959). 

Gallformers ID Notes

## *Xanthoteras* Ashmead, 1897, re-established genus

Beutenmueller (1911) originally described *Dryophanta clavula*. Subsequently, Kinsey (1930: 215) reassigned this taxon as a variety of *Cynips (Antron) teres* (Weld). However, due to the preoccupation of the name *clavula*, he proposed the replacement name *Cynips teres* var. *clavuloides*. Later, Burks (1979) recognized this species within *Xanthoteras* Ashmead, 1897, a placement later formalized by Dailey and Menke (1980), who transferred it to *Xanthoteras* and designated a lectotype. Finally, Melika and Abrahamson (2002) transferred this species to *Atrusca*.

Based on a critical re-examination of the diagnostic character states, we re-establish the genus *Xanthoteras* gen. rev. and transfer back the species *X. clavuloides* (Kinsey, 1930), comb. rev., while recognizing that the limits of this genus are still uncertain and require revision. Recent phylogenetic studies have shown that the genus *Atrusca* and *X. clavuloides* comb. rev. are closely related, along with *Cynips* (= *Besbicus*), *Philonix*, and some *Sphaeroteras* (Nicholls et al. 2017; Melika et al. 2021a, 2021b; Nieves-Aldrey et al. 2021; Cuesta-Porta et al. 2023). However, the morphology of *X. clavuloides* comb. rev. does not align with *Atrusca*, given the presence of the malar sulcus. Preliminary molecular analyses (James Nicholls, unpublished data) suggest that *X. clavuloides* comb. rev. forms a distinct lineage independent from *Atrusca* and *Sphaeroteras*. Thus, a detailed revision of all species from *Sphaeroteras* and *Xanthoteras* is necessary to establish the true limits of the two genera.