Quercus michauxii added tentatively as a host based on this unconfirmed observation.

Quercus oglethorpensis added tentatively as a host based on this unconfirmed observation.

Neuroterus vesicula and Andricus pisiformis are both small, globular, often dark-surfaced bud galls found on white-group oaks in the spring. Based on the photos Weld provides of Andricus pisiformis, that species is distinguished by many prominent, near-circular, white-colored spots. According to Scott Digweed (personal communication) galls with that appearance on Quercus macrocarpa have been found to contain adults matching N vesicula.

Adults reared from galls on Quercus stellata initially identified as A pisiformis due to the presence of spots were found to match N vesicula. However, on further examination, the spots on these galls (and many others on Q stellata) were seen to be somewhat distinct from those on A pisiformis. The spots on these galls are smaller, more irregular in shape and often less clearly bounded, with networks of lighter-colored cracks extending from spots, sometimes connecting many of them.

Aside from gall appearance, according to the literature, A pisiformis adults emerge up to a year after the appearance of the gall, while N vesicula adults emerge the same spring. A pisiformis is also easily distinguished by cross section. It contains a hard internal larval cell surrounded by a soft, fleshy external shell.

Adults determined to be A pisiformis by adult anatomy were found to be very distinct from N vesicula in UCE genetic analysis by Ward et al.