Callirhytis difficilis

Andricus difficilis

Cynipidae

Kokkocynips

Quercus hemisphaerica

Alabama

Arkansas

Florida

Georgia

Louisiana

Maryland

Mississippi

North Carolina

Pennsylvania

South Carolina

Texas

Virginia

Quercus incana

Oklahoma

Quercus inopina

Quercus laevis

Quercus laurifolia

Quercus myrtifolia

Quercus nigra

Delaware

Illinois

Indiana

Iowa

Kansas

Kentucky

Missouri

Nebraska

New Jersey

New York

Ohio

Tennessee

West Virginia

Quercus phellos

Connecticut

Re-description and systematic re-appraisal of the genus Kokkocynips Pujade-Villar & Melika, (Hymenoptera: Cynipidae: Cynipini), including new combinations of Nearctic species and the description of a new species from Panama

Cynipid galls of the eastern United States

Kokkocynips difficilis (agamic)

Callirhytis difficilis

Quercus cinerea [incana], laurifolia, myrtifolia, nigra, phellos
Stem galls, detachable
Small, rugose, grayish, in a cluster or rows from furrows in bark, dropping when mature in Oct.

[Photo caption]
On Q cinerea [incana]. Also on Q nigra, myrtifolia, phellos, laurifolia. Collected in Oct 1917 in AR. Galls gave adults Sept 29 and Dec 8 1919 and Oct 10, 1920.

Callirhytis difficilis (Ashmead 1887)

Hosts: Quercus inopina, myrtifolia

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

Using gall wasps on oaks to test broad ecological concepts

Kokkocynips difficilis (Ashmead, 1887) n. comb.

Andricus difficilis Ashmead, 1887. in: Tr. Amer. Ent. Soc, V. 14 p.143.
Callirhytis difficilis (Ashm.): Mayr, 1902. Verh. Ges. Wien, v. 52, 289.

Gall: small (12 X 15 mm), irregularly rounded, densely rugose, reddish when young and turns grayish following gall maturation, slightly flattened at sides, the rugosities arranged transversally in five to six rows. These galls occur in clusters, emerging in rows from fissures or slits in the terminal twigs; when mature fall to the ground (Ashmead 1887).

Host plant: Quercus laurifolia, Q. cinerea [incana], Q. catesbaei [laevis], Q.nigra, Q. myrtifolia and Q. phellos (Weld 1959)

Biology: only known from the asexual generation. According to Ashmead (1887), the adults emerge from galls from August to September; Weld (1959) noted that adults also emerged later in the year up to December.

Distribution:  South-eastern  North  America,  from  Maryland  southwards  to  Florida  and  westwards  to  Texas (Burks 1979, pers. obs.).

Quercus hemisphaerica added as a host based on [this observation](https://www.inaturalist.org/observations/86782824)--see discussion in comments. 

Gallformers ID Notes