Dryocosmus quercuspalustris

Family: Cynipidae | Genus: Dryocosmus
Detachable: integral
Color: green, black
Texture: hairy, hairless, succulent
Abdundance: abundant
Shape: sphere
Season: Spring
Alignment: integral
Walls: thin
Location: bud, petiole, upper leaf, lower leaf, between leaf veins, flower
Cells: free-rolling
Possible Range:i
Common Name(s):
Andricus palustris
Callirhytis palustris
Callirhytis quercus-palustris
Cynips quercus palustris
Diplolepis palustris
Dryophanta palustris
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On the Cynipidae of the North American Oaks and their Galls

Cynips quercus palustris n. sp.

Quercus palustris. Pin oak.

Globular, hollow galls on the buds and young leaves. Diameter 0.35-0.4.

Shell green, succulent, hollow on the inside, containing a whitish, globular body, about 0.1 in diameter, which rolls freely about, not being fastened to the shell.

I found these galls quite commonly very early in the spring, on the buds of the oak, before any leaves had appeared. At that early season already, the globular, whitish body contained the pupa. When the leaves came out, I observed the same gall on them, generally close by the leaf-stalk. The fly was obtained from the galls brought home on the 17th of May. In the woods, most of the galls were found empty on the 25th of May. Still, some of them contained the fly yet.

Several galls of this kind were observed on the pin oak; they seem to occur also on other oaks, but I neglected to observe on which, chiefly on account of their appearing before the leaves were developed. The gall shrinks completely when dried but can be preserved in spirits.

- Baron Osten Sacken: (1861) On the Cynipidae of the North American Oaks and their Galls©

Reference: https://www.biodiversitylibrary.org/item/22852#page/82/mode/1up

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