For some reason, when I saw this gall I immediately thought of the recent political campaign. At a distance it looks like hair but close up (below) it is more fuzzy strands. It was attached to the center vein of a white oak leaf. I had recently written about Fuzzy Orange Galls and it didn't look like the spiky Callirhytis furva.
|Not hair on closeup - definitely a leaf gall|
Galls are identified by the species they appear on as well as their individual appearance. Looking for information on the cynipid gall wasp C. furva contains is an exercise in frustration. In this case, Bugguide references a 1911 book, California Gall-making Cynipidae: With Descriptions of New Species by Mary Isabel McCracken which you can download for free. The description:
"Gall - Brown elliptical, thin-walled, surface reticulate and covered with a rusty brown mat of fibers, two to many balls on a leaf, lying adjacent or strung along on the midrib, usually beginning at the base of the leaf, at least 1/2 mm in diameter. Persistent, falling to the ground with the leaves in the fall. Adults emerge in the breeding room in March."Identification in 1911 required detailed descriptions compared to today when even a 5th grade WOLF student has a camera (now called a cellphone) to compare with pictures online and we can even send the question to a world-class expert with an answer in minutes. Inaturalist and Project Noah can help you identify galls by pictures, and commercial photographers are happy to sell you their images for publication. Mary Isabel McCracken would be so jealous.
|Gall cut open - REK|
Somehow it is reassuring that in this day of instant information, Snapchat, Wikileaks, and the hacking of the Internet, this little wasp can remain photographically anonymous.