| C. dugèsi simulatrix | on Q. grisea, Q. undulata, Q. Gambelii, Q. arizonica, Q. oblongifolia |
| C. dugèsi brevipennata | on Q. grisea, Q. Gambelii, Q. fendleri |
| C. bella bella | on Q. grisea, Q. undulata, Q. pungens, Q. arizonica, Q. reticulata, Q. oblongifolia |
| C. mellea anceps | on Q. alba, Q. stellata, Q. floridana, Q. Chapmanii, Q. breviloba |
| C. mellea bifurca | on Q. stellata, Q. floridana |
| C. mellea litigans | on Q. stellata, Q. floridana |
| C. mellea Carolina | on Q. alba, Q. stellata |
| C. nubila nubila | on Q. arizonica, Q. oblongifolia |
| C. nubila russa | on Q. arizonica, Q. oblongifolia |
| C. nubila incompta | on Q. reticulata, Q. glaucophylla |
| C. villosa acraspiformis | on Q. grisea, Q. undulata, Q. arizonica, Q. Tourneyi |
| C. villosa expositor | on Q. arizonica, Q. grisea |
| C. villosa apache | on Q. arizonica, Q. grisea |
| C. gemmula fuscata | on Q. Michauxii, Q. Mühlenbergii |
| C. gemmula prinoides | on Q. prinoides, Q. Mühlenbergii |
| C. hirta hirta | on Q. Prinus, Q. Michauxii |
It will be observed that in several cases a single species of Cynips occurs on such distinct oaks as Quercus alba, Q. macrocarpa, and Q. Michauxii; Q. alba and Q. stellata; etc. Such cases, commonly reported in literature on galls, are usually based on misdeterminations, but the present records have been carefully checked and may be verified from insect material in our collections.
Concerning the relative importance of insect and gall characters in the differentiation of species among Cynips:
52 species have insect structures more distinctive than galls,
24 species have galls more distinctive than insect structures,
17 species have galls and insects equally distinctive.
In more than half the genus the insects are more diagnostic than the galls, and there are even cases of distinct insects with practically identical galls. Most of these cases involve such closely related insects as we have called varieties in the systematic portion of this paper, but the following cases involve the second taxonomic category:
Cynips fulvicollis and C. plumbea
C. dugèsi and C. bella
C. pezomachoides and C. gemmula (certain var. only)
C. pezomachoides and C. hirta (certain var. only)
C. arida and C. mellea
