and Illinois on white oaks. There are two generations per year. 
Adults of the first generation emerge in May from galls produced 
on the preceding year’s growth. Second generation adults emerge 
from green galls. Females of this generation lay their eggs in 
the same galls from which they emerge. 
Neuroterus floccosus (Bass.), the oak flake gall, produces small, 
hemispherical galls from 1.5 to 3.5 mm. in diameter on the lower 
surface of terminal] leaves of white oaks. These galls are covered 
with white hairs and often occur in large numbers on a single 
leaf. Heavily infested leaves curl and are unsightly on shade trees. 
Neuroterus noxiosus (Bass.), the noxious oak gall, occurs on 
swamp white oaks from New England to Virginia and in the 
Central States. Heavily infested trees may be severely disfigured. 
Amphibolips confluenta (Harr.), the large oak-apple gall (fig. 
198), occurs from southern Canada to Virginia. It produces galls 
on the leaves or leaf petioles of various oaks, principally red, 
black, and scarlet. These galls are quite large, from 12 to 50 mm. 
in diameter, and greenish to brownish in color, depending on age. 
The related species, A. fulginosa Ashm., produces globose galls 
on the sides of willow and laurel acorn cups in Florida. 
COURTESY ILL. NAT. HIST. SURV. 
FIGURE 196.—Gouty oak galls 
caused by Callirhytis punctata. 
COURTESY AMER. MUS. NAT. HIST. 
FIGURE 197.—Oak potato gall on 
white oak caused by Neuroterus 
quercusbatatus. 
481 
