Cynips gemmula var gemmula form prinoides

Philonix prinoides

  Cynips prinoides

 Philonyx prinoides

Cynipidae

Acraspis

Quercus michauxii

Alabama

Arkansas

Delaware

Florida

Georgia

Illinois

Indiana

Kentucky

Louisiana

Maryland

Mississippi

Missouri

New Jersey

North Carolina

Oklahoma

South Carolina

Tennessee

Texas

Virginia

Quercus muehlenbergii

Connecticut

Iowa

Kansas

Massachusetts

Michigan

Minnesota

Nebraska

New Mexico

New York

Ohio

Pennsylvania

Vermont

West Virginia

Wisconsin

Ontario

Quercus prinoides

Maine

New Hampshire

Rhode Island

The species of Biorhiza, Philonix and allied genera, and their galls

The Gall Wasp Genus Cynips

Acraspis prinoides (agamic)

Philonix prinoides

Cynips prinoides
Philonix prinoides
Acraspis prinoides

Gall. On the upper or under side of the leaves of dwarf chestnut oak (Quercus prinoides), usually on the mid rib. In August and September. Monothalamous. Hard and woody. Globular with numerous cone-like projections, each with a long or short bristle. Green or yellowish usually tinged with red. Internally there is a rather large larval chamber. Diameter 6 to 12 mm.

Habitat: NY, NJ, OH 

Cynips gemmula variety gemmula
agamic form prinoides

Cynips prinoides
Philonix prinoides
Philonyx prinoides
Acraspis prinoides

GALL. — Averaging nearer 8.0 mm., altho up to 11.0 mm. in diameter; always monothalamous ; on leaves of Quercus prinoides, Q. Michauxii, Q. Muhlenbergii, and possibly other chestnut oaks. Figure 327. 

RANGE. — Massachusetts: Springfield (gall, acc. Stebbins 1910). Eastern part (bisex. form, Thompson in Bost. Soc. coll.). Connecticut: Waterbury (bisex. form, Bassett coll.). New York: Oriskany Falls (galls, J. A. Douglass acc. Felt 1912). Vicinity of New York City (acc. Beutenmiiller 1904). Staten Island (acc. Weld 1928). New Jersey: Lakehurst (Beutenmiiller and W. T. Davis in Kinsey coll.). Toms River (Beutenmiiller, types). Richland (Kinsey coll.). Virginia: Cape Charles (Kinsey coll.). Ohio: Cincinnati (gall, Braun in Amer. Mus.). Indiana: Bloomington (C. M. Kinsey coll.). Benham (G. F. Hyatt in Kinsey coll.). Aurora (Kinsey coll.). Kentucky: Lebanon (Kinsey coll.). Tennessee: Tazewell (gall, Kinsey coll.). Missouri: Ranken (Kinsey coll.). Occurring in the northeastern United States from Massachusetts to southern Indiana and Missouri, south in the mountains to Kentucky and Tennessee, confined to areas in which chestnut oaks are found. Figure 62. 

This is the common variety of the species over the northeastern quarter of the United States. I find no appreciable difference between the northern Coastal Plain material on Q. prinoides (the source of the type) and our Middle-Western series of the insect on Q. Michauxii and Q. Muhlenbergii. In this failure to differentiate a Coastal Plain variety gemmula is matched by Cynips fulvicollis. 

In common with all the other Cynips of this part of the country, gemmula shows an extreme degree of individual variation that may indicate a hybrid origin of the variety, possibly dating from the Pleistocene glaciation which projected northern varieties into the ranges of southern varieties and which ultimately, upon the glacial retreat, left a great territory where the hybrid individuals developed into hybrid populations deserving taxonomic recognition (see pp. 55 to 60) . The Ozark variety fuscata would appear to be the southern parent of gemmula, for gemmula intergrades into fuscata in southern Indiana (and probably elsewhere). Unlike the other species of Cynips involved in this area, the northern parent of gemmula is not known from any pure population in the north, possibly because most of the chestnut oaks, which are the hosts of our insect, do not range as far north as other white oaks. If they did extend further north in the former day, there may have been a northern parent of gemmula which does not now survive. Nevertheless, in the line series of gemmula which we have from Bloomington, in southern Indiana, there are a few individuals that are much smaller and darker, with smoother and more naked body surfaces. Since these are the very characters which distinguish the most northern varieties of Cynips pezomachoides, C. fulvicollis, C. hirta, C. folii, C. divisa , and C. longiventris, it is possible that these small insects of gemmula are Mendelian segregates from the hybrid stock, and that these represent the northern parent of gemmula. It is, on the other hand, possible that these small individuals represent local mutants. We have described them as variety suspecta. Out of the 606 insects we have bred from Bloomington material, we find 23 (= 3.8%) have this small and dark form, 22 (=3.6%) seem characteristic fuscata, and the remaining 92.6% are the variable hybrid series which is gemmula. 

The galls of the agamic gemmula are to be found late in August (acc. Beutenmuller) but they probably appear much earlier than this — perhaps late in June as with other species of Cynips. The galls were of full size at Lakehurst, New Jersey, on September 14 (1904, W. T. Davis in Kinsey coll.), and at Bloomington, Indiana, early in September (1928). The insects had not yet emerged from the galls I collected at Rich- land, New Jersey, on October 13, at Cape Charles, Virginia, on October 17 (both in 1919), and at Ranken, Missouri, on October 29 (in 1926). Material in the American Museum records unemerged adults in the galls on an October 26. Our emergence dates for this insect are December 1, 2, 4, 6, 8, 10, 16, 18, and 21. 

Acraspis gemula Bass.
var. gemula bass.
Agamic form, prinoides Beutm.

Gall, globular, spined, monothalamous, on leaves.

Adults, Dec.

On Q prinoides

Plant Galls and Gall Makers

Acraspis prinoides

Quercus prinoides
Leaf galls, detachable
Globular, 12 mm in dia, covered with cone-shaped projections, on upper surface of leaf in late Aug. Light green tinged with red, one-celled. Type host. Adults emerge in Dec.

[Photo caption (no photo)]
On Q prinoides. On Long Island galls were just starting on July 23. Galls from the pine barrens of NJ contained adults Oct 21; some emerged Dec 26.

Cynipid galls of the eastern United States

Host association with Q muehlenbergii determined from iNat observations [(eg)](https://www.inaturalist.org/observations/17425211) with confirmed host IDs. Not verified by adult wasp anatomy. Observations on Quercus montana [1](https://www.inaturalist.org/observations/58655124) [2](https://www.inaturalist.org/observations/61617761) are broadly similar but not definitive. 

Gallformers ID Notes