Midrib or petiole swellings
Oak petiole gall. Somewhat globular, conical above with a depression at apex, hard, green, polythalamous, the larval cells radiating out from the center. On the petiole or basal part of midrib, usually several in close proximity on the tree. In May and June, the adults emerging in late June. On Q. alba, bicolor, and macrocarpa.

Andricus petiolicola (O.S.)

Quercus alba, michauxii, prinoides
Leaf galls, integral
Abrupt, almost woody, with a scar at apex, 10-15 mm in dia., at base of leaf blade in early spring.

Quercus bicolor
Leaf galls, integral
An abrupt firm enlargement, 10 mm in dia., with a scar at apex, at base of leaf blade, green and many-celled.

Quercus macrocarpa
Leaf galls, integral
Abrupt firm swelling with a scar at apex on basal third of leaf in spring, green, many-celled.

Quercus prinus
Leaf galls, integral
Abrupt, almost woody swellings with a scar at apex, 10-15 mm in dia., at base of leaf blade in spring, green, many-celled.

Quercus stellata
Leaf galls, integral
Abrupt, firm, green swelling with scar at apex, at base of leaf blade in early spring.

[Photo caption]
Andricus petiolicola (O.S.) On Q prinus. Also on Q michauxii, bicolor, prinoides, macrocarpa. Adults of both sexes emerged June 21 (VA), June 27 (DC); July 5-13 (ON). Females were observed ovipositing in terminal buds.

Cynips q. sculptus n. sp.

Quercus montana.

Club-shaped galls on the petioles of the leaves half an inch in diameter, hard and woody when fully matured. The gall is probably identical with a species described by Baron Osten Sacken as found on Q prinos. His description is as follows: "Swelling of the leaf stalk at the basis of the leaf, or, sometimes, of the midrib near the base." When on the petiole "subconical or club shaped; rounded when they occur on the midrib."
His specimens produced only parasites, and as mine have produced, besides many parasites, a few true gall flies, I will describe them under the specific name he has given to the parasite reared from the same gall.

Cynips q. petiolicola n. sp.

Gall from Quercus chinquapin [Quercus muehlenbergii]

Compared with the last species [Cynips q. sculptus] I can discover no difference in the gall, and little in the insect. I have galls from the petioles of the leaves of the white oak very much like those last described.

Andricus petiolicola (Bassett)

Galls of this species were noticed at several localities and on several hosts. On the rock chestnut oak, Q montana [in NY, PA, MA, DC, VA.] On Q. macrocarpa [in IL, NY] where they contained pupae June 30, 1914. On Q. bicolor [in IL] where adults began to emerge June 23. On Q. alba [in IL, MO, VA, MA, NY]. On Q. stellata [in OK, TX, AL, FL, VA.]

Andricus petiolicola Bassett, Oak petiole gall.
Cynips quercuspetiolicola
Cynips petiolicola
Andricus petiolicola
A woody, club-shaped gall on petiole or midrib of leaf. Polythalamous. About 15 mm in diameter. Green becoming brown. Common on white oak, Quercus alba, chestnut oak, Q. prinus, and dwarf chestnut oak, Q prinoides.

Andricus concolorans, new species

Cynips cicatricula (gall)
Andricus cicatricula (gall)
Callirhytis cicatricula (gall)
Andricus cicatriculus (gall)
(Andricus cicatriculus belongs to Ceroptres and is an inquiline in the gall of Cynips concolorans)

Gall "Polythalamous galls on the midvein of the leaves of Quercus alba, prinus, prinoides, never more than one on a leaf, and situated sometimes at the base, but usually from one-fourth to one-half way from the base, rarely above the middle. They project one-third below and two-thirds above the surface of the leaf. The gall is solid and somewhat fibrous, and in its shorter diameter measures about one-half inch and in the longer from five to seven-eighths of an inch. The larval cells radiate in all directions from the center of the gall and are quite numerous. There is at or near the summit of the cone a small scar or indentation" - Bassett 1881 p 101.

Range: MA, RI, CT, NY

Thompson found the adults emerging late in June.

Andricus quercuspetiolicola (Osten Sacken 1861)

Hosts: Quercus chapmanii

[Sexual generation integral leaf gall found in the spring.]