598 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
leaves of swamp oak (Quercus bicolor) in the Eastern States. The 
galls are small (1.5 to 3.5 mm.), hemispherical, and covered with 
white hairs. As many as 200 galls may be found on a single leaf. This 
causes malformation and curling. Adult insects, as well as galls in 
all stages of growth, are present in July. 
Galls produced by Biorhiza forticornis Walsh, the oak fig gall (fig. 
182), have been recorded on the leaves, stems, and twigs of white oak 
(Quercus alba), scrub 
oak (Q. ilicifolia), and 
dwarf chinquapin oak 
(Q. prinoides) in the 
os Eastern States. These 
= galls are reddish bladder- 
Sa hike growths in dense 
= EN clusters, and range from 
=\ I Y, to.1% inch in diameter. 
The adult female de- 
Figure 180,—The large oak-apple gall (Amphi- posits a number of eves a 
bolips confluentus). (Courtesy Amer. Mus. : S55 
Nat. Hist.) short distance from one 
another, apparently sink- 
ing them into the wood beneath the bark. A smooth round sweling 
soon appears above the egg. This swelling bursts and small round 
granules the size of a pinhead protrude from the opening. As these 
granules, or galls, grow they resemble small clusters of grapes. The 
larva lies in a small oval cavity at the base of each gall. Most of the 
adults emerge before winter, but some of the insects overwinter within 
can) 
the galls and emerge in June. 
FIGURE 181.—The oak flake gall (Newroterus floccosus). (Courtesy Amer. Mus. 
Nat. Hist.) 
SEED AND FLOWER GALLS 
The succulent oak galls formed by Callirhytis (Dryophanta) pal- 
ustris O. S. (fig. 183) are common early in the spring, appearing on 
red oak (@uercus borealis) and pin oak (Q. palustris) im the eastern 
half of the United States. The growths are somewhat spherical, 8 to 
4 inch in diameter, and consist of a distinctly fleshy wall and a rather 
