88 
Indiana University Studies 
C. dugesi simulatrix 
on 
C. dugesi brevipennata 
on 
C. bella bella 
on 
C. mellea anceps 
on 
C. mellea bifurca 
on 
C. mellea litigans 
on 
C. mellea Carolina 
on 
C. nubila nubila 
on 
C. nubila russa 
on 
C. nubila incompta 
on 
C. villosa acraspiformis 
on 
C. villosa expositor 
on 
C. villosa apache 
on 
C. gemmula fuscata 
on 
C. gemmula prinoides 
on 
C. hirta hirta 
on 
Q. grisea, Q. undulata, Q. Gambelii, Q. 
ccrizonica, Q. oblongifolia 
Q. grisea, Q. Gambelii, Q. fendleri 
Q. grisea, Q. undulata, Q. pungens, Q. 
arizonica, Q. reticulata, Q. oblongifolia 
Q. alba, Q. stellata, Q. floridana, Q. 
Chapmanii, Q. breviloba 
Q. stellata, Q. floridana 
Q. stellata, Q. floridana 
Q. alba, Q. stellata 
Q. arizonica, Q. oblongifolia 
Q. arizonica, Q. oblongifolia 
Q. reticulata, Q. glaucophylla 
Q. grisea, Q. undulata, Q. arizonica, Q. 
Toumeyi 
Q. arizonica, Q. grisea 
Q. arizonica, Q. grisea 
Q. Michauxii, Q. Miihlenbergii 
Q. prinoides, Q. Miihlenbergii 
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. macro- 
carpa, 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 mate- 
rial in our collections. 
Concerning the relative importance of insect and gall char- 
acters 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 sys- 
tematic portion of this paper, but the following cases involve 
the second taxonomic category : 
Cynips fulvicollis and C. plumbea 
C. dugesi and C. bella 
C. pezomachoides and C. gemmula (certain var. only) 
C. pezomachoides and C. hirta (certain var. only) 
C. arida and C. mellea 
