I just stepped out to grab a couple of oak leaves to feed some sawfly larvae that I’m accidentally raising, and on the way I peeked under a hickory branch that was jutting out over the road, and discovered a nice assortment of galls on the undersides of the leaves. Just like hackberry, hickory is the host to a midge genus whose species produce detachable leaf galls with a wide variety of shapes. There are 56 known Caryomyia species, most of which Raymond J. Gagné described for the first time in 2008, in a paper that he was kind enough to send me a few years ago*.
I’ve wanted to find this last one ever since I came across it in the paper. Its namesake:
For even more hickory midge galls, see BugGuide.
* Gagné, Raymond J. 2008. The Gall Midges (Diptera: Cecidomyiidae) of Hickories (Juglandaceae: Carya). Memoirs of the American Entomological Society 48:1-147.