Cecidomyia sp.

Fusiform ribbed or carinate mid or lateral vein folds on the under surface, length 6 to 8 mm, diameter 3 to 4 mm.

Cecidomyia quercus majalis

Quercus rubra

Green or brown, narrowly oval, inflated galls produced along the veins on the under side of the leaves. The surface of the gall is netted with veins. Oak Vein Gall.

Cecidomyia majalis

Hosts Quercus rubra, coccinea

A flat pouch-like gall on the under side of the leaf. The opening which extends the entire length of the gall is on the upper side. It is produced by a folding of the blade of the leaf; this fold is parallel with and very close to the midrib or a main vein.

Along the main line of its attachment to the leaf, diameter 4-7 mm.

[Photo caption]
Fig 27. Cecidomyia majalis on the leaf of Quercus coccinea. Section at right angles to the midrib. The folding of the leaf is shown and the uniform character of the mesophyll of the gall.

Cecidomyia quercus majalis n. sp.

Blister-like gall of Cecidomyia on young leaves of the pin-oak (Quercus palustris).

Generally, these galls occur on the principal ribs of the leaf; sometimes between the ribs. They are oblong, blister-like, hollow; surface somewhat uneven, wrinkled, walls thin; color pale green or reddish. They bulge out on one side of the leaf and have a longitudinal slit on the other. Galls projecting on the under side of the leaf and having the slit on the upper side seem to be somewhat more common than those of the opposite description. The slit can be opened without injuring the gall by gently pulling at the sides. Such galls which grow upon a rib show a trace of it on their longitudinal diameter. The larva, which can be taken out of the slit without lacerating the gall, is rather larger than the majority of the larvae of Cecidomyia, (about 0.2 of an inch long.) and not reddish, as usual, but white, smooth. The larva drops to the ground through the slit at a certain period of its development; hence, empty galls are often found. Found in considerable numbers in the Central Park, N. Y., in May, 1869.

Cincticornia majalis 0. S.

Vein galls.
Gall very similar to, if not identical with the above [Cincticornia podagrae: A narrow, dark purplish, fusiform, thin-walled swelling on the under side of the mid or lateral veins may contain two or more orange larva, length 8 mm.]

Cincticornia majalis [this description differs from those given in other sources and should be viewed skeptically]

Vein galls
Gall very similar to, if not identical with the above. [A narrow, dark purplish, fusiform, thin-walled swelling on the under side of the mid or lateral veins may contain two or more orange larvae, length, 8 mm.]

Cecidomyia majalis

Cecidomyia quercus majalis

Quercus rubra

An oblong blister-like gall along the principal veins, usually on the under side of the leaf. It opens by a slit on the opposite side which may be opened by pulling the leaf. Green becoming brown. Sometimes veins show on the gall. Thin-walled. The larva drops to the ground to transform. Common on scarlet oak, black oak, red oak, and pin oak. (Quercus coccinea, velutina, rubra, and palustris).