Cynips quercus centricola

Holcaspis centricola

Atrusca centricola

Cynips centricola

Loxaulis centricola

Dryophanta centricola

Diplolepis centricola

Disholcaspis centricola

Diplolepis quercus-centricola

Diplolepis quercus-rubrae

Cynips rubrae

Dryophanta rubrae

Cynips q centricola

Cynipidae

Atrusca

Quercus stellata

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Cynipid galls of the eastern United States

The Gall Wasp Genus Cynips

Atrusca quercuscentricola (agamic)

The Smaller Empty Oak-apple is found on the post-oak and measures three fourths of an inch or less in diameter. It also differs from the preceding in that the outer shell is mottled.

A manual for the study of insects

Holcaspis centricola (Osten Sacken)

Cynips quercus centricola
Cynips q centricola
Cynips centricola
Loxaulis centricola

Gall. (Plate IX, Fig. 1.) On the undersides of the leaves of post oak (Quercus minor [stellata]). Globular flattened at base and attached to the leaf by a small nipple. Thin shelled white, sometimes tinged with pink and covered with a white pubescence, this being the character of the under side of the leaf of the post oak. Internally there is a central kernel which is held in position by numerous, white, silky filaments, radiating from the kernel to the shell of the gall. Diameter 15 to 20 mm. 

Habitat. Washington, D. C.; New Jersey; Indiana. 

A very distinct species and different from all other known Holcaspis. In the adult the parapsidal grooves extend from the shoulders, where they are widely separated, backward to the scutellum, where they are close together. The line at base of wing is curved anteriorly and the wings are clouded apically and on the anal vein. The gall superficially resembles that of Amphibolips inanis. It is possible that the species may not belong to the genus Holcaspis and I place it in this genus tentatively. The types are in the Museum of Comparative Zoology at Cambridge, Mass. 

The species of Holcaspis and their galls

Diplolepis centricola

The gall of this species is a spotted oak apple usually found singly on under side of leaf of Quercus stellata in the fall. The writer has collected them at Ironton and Poplar Bluff, Mo.; Hoxie and Texarkana, Ark.; and Tuskahoma, Okla. Ashmead collected galls at Asheville, N. C, and J. Angus at West Farms, N. Y. Galls at Ironton contained adults November 14 and some had already chewed their way out of the inner cell. Some emerged November 27, and December 8. Galls at Hoxie contained pupae October 10, and adults November 17. At Washington adults were found inside the galls October 9, and 20, and on November 1, some had chewed out of the inner cell. 

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

Cynips (Atrusca) centricola
agamic forms

GALL. — A large, spherical, spotted or unspotted, thin-shelled leaf gall with rather sparse, radiating fibers. Monothalamous. Strictly spherical except where flattened a bit at the point of attachment; ivory to apricot or more pinkish in color, some galls well covered with purplish spots; smooth and often shining, only very microscopically roughened, young galls with a microscopic, stellate pubescence; up to 26.0 mm., averaging under 20.0 mm. in diameter. Internally hollow except for the thick-walled larval cell which is up to 4.0 mm. in length, for the relatively few, silky, radiating, branched fibers that hold the larval cell in position, and for a few shorter, incomplete, branched fibers also located on the inner wall and on the larval cell. Attached by a minute point to a vein; usually on the under surface of a leaf, on Quercus stellata. Figure 197. 

RANGE. — Known from New York to Florida, Missouri, and Texas; probably not extending much further than this. Figures 47, 48. 

This is the oldest and most commonly known American species of Cynips, but it is poorly represented in most collections. None of the published data, nor most of the collections I have made would indicate that it is ever abundant in any part of its range, but 1 have on several occasions found individual trees bearing more than fifty galls each. These galls are confined to the post oak, Quercus stellata, on the leaves of which they are strikingly beautiful objects. There are four known varieties, centricola from the Coastal Plain and its inland extensions, clivorum from the Southern Appalachians, strians from the Ozark area, and Karsch’s rubrae from Texas. The varieties are separable on only a few insect characters, and on the presence or absence of spots on the galls, and altho typical material from the center of each range is definitely determinable, hybrid material from areas between two of these ranges is not easily analyzed. The slow evolution in this species is in contrast to the more rapid evolution of such a species as Cynips mellea in the same range. 

The presence or absence of spots on the galls of this species was taken by Osten Sacken, in the original description of the typical variety, to vary with the age of the gall. It is possible that the amount of weathering has something to do with this, but I have unspotted galls of the normally unspotted variety clivorum collected on various date from October 24 to November 16, and spotted galls of the normally spotted varieties rubrae and strians from September 9 to January 21. Only with variety centricola do we regularly find galls of both types, and the data do not seem to show whether hereditary or environmental factors are concerned in this instance. 

The galls of centricola superficially resemble those of Amphibolips inanis, a black-oak species of the eastern United States; but inanis galls are distinguishable by their host and by their fewer, coarser fibers, and by numerous other points. The galls of centricola even more closely resemble those of the Pacific Coast species, Cynips mirabilis, but the galls of mirabilis have denser fibers inside. Mirabilis and centricola belong to distinct subgenera. Some of the unspotted galls of Cynips centricola clivorum also approach near identity with the galls of Cynips bella and Cynips dugesi.

Centricola is in several respects distinct from the other species of the subgenus Atrusca, but these differences are not fundamental enough to warrant the establishment of another subgenus for one species. 

[Kinsey goes on to describe four varieties; see paper for details]

Cynips (centricola) centricola Osten Sacken
agamic form

Cynips quercus centricola Osten Sacken, 1861, Proc. Ent. Soc. Phila. 1:53, 58. 
Holcaspis centricola Beutenmüller, 1909, Journ. N.Y. Ent. Soc. 17:46. Davis, 1918, Journ. N.Y. Ent. Soc. 26:48. 
Cynips centricola centricola Kinsey, 1930, Ind. Univ. Studies 84-86:297, figs. 47, 271, 284 (omitting the Illinois, Virginia, and Western Missouri records). 
Cynips centricola Davis, 1930, Bull. Brooklyn Ent. Soc. 25:233. 

To the data given in Kinsey 1930, add: 

RANGE.-Missouri: Mineola (galls only). North Carolina: Marshall (gall only). 

LIFE HISTORY..—Galls: Mature at end of September. Adults: In galls early in October and early in November. Emerging November 17, 26. December 8.

Cynips (centricola) clivorum Kinsey
agamic form

Cynips centricola clivorum Kinsey, 1930, Ind. Univ. Studies 84-86:300, figs. 48, 258-259, 269, 285. 

To the data given in the above monograph, add: 

RANGE.-Ohio: West Union, 6 N. Chillicothe (gall). Gallipolis, 6 N. Indiana: Boonville, 10 E (gall only). Illinois: Eddyville (O. Buchanan in Kinsey coll.). Kentucky: Sullivan, 1W (galls). Tennessee: Dickson, 7W. Jackson 3 S (gall only). Memphis, 12 E (gall only, Breland in Kinsey coll.). Virginia: Golansville

LIFE HISTORY..—Adults: November 2, 13, 20, 26. December 2, 3, 9, 15, 16, 18, 20, 24. January 2. Most of the emergence late in November and early in December. 

The new locality records put this Southern Appalachian species, clivorum, at additional points in the Ohio River Valley and in the western third of Tennessee. In the latter state, the distribution extends west to the Mississippi River, which is further west than anticipated. The black insect and unspotted galls make determinations of clivorum practically certain, for all of the other species of the complex have spotted galls (except for rare, unspotted, immature galls in centricola).

Cynips (centricola) strians Kinsey 
agamic form 

Cynips centricola strians Kinsey, 1930, Ind. Univ. Studies 84-86:304, figs. 48, 256-257, 286 (omitting Eddyville record). 
Cynips quercus-centricola strians Houard, 1934, Marcellia 28:47. 
Cynips quercus-centricola Houard, 1935, Marcellia 28:122. 

To the data given in Kinsey 1930, add: 

RANGE.-Missouri: Springfield, 7 SE (R. Voris in Kinsey coll.). Norwood, 5 E. Sullivan, 1NE. Winona. Arkansas: Imboden, 5 SW (gall, B. C. Marshall in Kinsey coll.). Busch, 4 E. Sheridan, 4N. Prairie Grove, 4 E. Conway, 4 E. Hazen, 5 E. Jasper, 4 S. Oklahoma: Muldrow, 2W. Eldon, 4 E (gall only). Louisiana: Wyatt (gall only). 

LIFE HISTORY..—Pupae: October 10. Adults: November 26. December 6, 10, 12, 13, 20, 22, 24. January 5, 30. February 2. Most of the emergence in mid-December.

The new records show the extensive range of this species through the Ozarks of Missouri, Arkansas, and Easternmost Oklahoma. The occurrence as far south as Sheridan, Arkansas (and possibly in Northern Louisiana) suggests that strians may be the same as Karsch's rubrae which came, presumably, from Texas; but it will be well to avoid mistaken synonymy by maintaining the two as distinct for the time being. If material from Eastern Texas, and a study of the type of rubrae (at the Berlin Museum) shows it to be the same as strians, it will be easy enough then to combine the nomenclature and data. 

The spotted galls of strians are practically the same as those of centricola, differing perhaps in averaging smaller in diameter. Previously we considered that the well-developed median groove (found in most of the types) would always separate strians from centricola, but the more extended material which we now have from the Ozarks shows so much individual variation in this character that we must depend on the nearly uniform black color and the less triangulate tip of the second abscissa of the radius of strians as the best characters for distinguishing the insects. 

Cynips (centricola) rubrae (Karsch)
agamic form

Diplolepis quercus-rubrae Karsch, 1880, Zeitschr. gesammt. Naturw. 53:293, pl. 6 figs. 4a,b.
Cynips centricola rubrae Kinsey, 1930, Ind. Univ. Studies 84-86:301, figs. 47, 274, 275.
Diplolepis centricola err. syn. Weld, 1931, Proc. Ent. Soc. Wash. 33:224.

To the data given in Kinsey, 1930, add:

RANGE.-Texas: Greenville (galls only).

Weld (1931) compared specimens of centricola from Washington, D. C., with the Karsch types of rubrae at the Berlin Museum, and concluded that the two were synonyms. They are clearly in the same complex, but Weld's synonymy cannot stand until the characters of the several species in the group are taken into consideration. It is more likely that my strians is a synonym of rubrae. See the note under strians in the present study. 

Origin of higher categories in Cynips

Atrusca centricola

Quercus stellata
Leaf galls, detachable
A spotted oak apple on under side of leaf in fall, usually single.

[Photo caption]
On Q stellata. Adults Nov 27-Dec 8.