FAMILY CYNIPIDAE 
THE GALL WASPS 
This large family of several hundred species consists largely of 
species which produce galls on their plant hosts in which they live 
and feed during the larval stage. Many others live in galls pro- 
duced by other insects, and a few are parasitic on other insects. 
The adults are small to extremely small and usually black. They 
are distinguished by the abdomen which is oval, shining, some- 
what compressed, and almost covered by the first tergite. Many 
gall-forming species produce two quite different generations per 
year. One generation develops during the summer in one type of 
gall. Adults appear in the fall and consist entirely of partheno- 
genetic females. Eggs laid by these females give rise to larvae 
which produce an entirely different kind of gall. Adults of this 
generation, consist of both males and females, and may be quite 
different in appearance from those of the first generation. 
It is estimated that 86 percent of the known gall-forming 
species produce galls on oaks and are confined to them (419). 
There are 717 species listed as occurring in the United States and 
Canada, 76 percent of which form galls on oaks (550). | 
The females deposit their eggs in the tissues of all parts of the 
host, from the roots to the flowers. Gall production is believed to 
result from the reaction of the cambium and other meristematic 
tissues to stimuli produced by the larvae. The great majority of 
species are of little or no economic importance. However, certain 
species which produce large irregular galls on the smaller 
branches are capable of causing injury (fig. 195). Infested 
branches may be disfigured or even killed. Occasionally, entire 
trees are killed. On the other hand, galls produced by certain other 
Species are economically valuable: Some have long been used in 
the manufacture of ink and in dyeing and tanning; others serve 
as a source of winter food for bees. One, the deciduous oak gall, is 
occasionally abundant enough on black oak in Missouri to be used 
as food for hogs, cattle, sheep, turkeys, and chickens (418, 420). 
Some of the more common and important gall-forming species are 
discussed below. 
Callirhytis floridana (Ashm.) occurs from Virginia to Florida 
and Missouri and Arkansas. It produces slender, elongate swell- 
ings from 12 to 75 mm. long on branches close to the ground of 
Chapman, post, and dwarf post oaks. Large acreages of dwarf 
post oaks were nearly all killed during an outbreak in eastern 
North Carolina in 19385 (420). 
Callirhytis punctata (O. 8.), the gouty oak gall, occurs from 
southern Canada to North Carolina and Illinois. It produces galls 
(fig. 196) on the twigs and smaller limbs of scarlet, pin, and 
black oaks. These galls are about 12 to 38 mm. long and they fre- 
quently occur so close together that they form practically con- 
tinuous masses. This species has alternate generations. The first 
produces small blisterlike galls on the leaves near the veins in the 
spring. The second produces gouty galls during the summer. In 
heavy infestations, twigs, fairly large branches, and even entire 
trees may be killed. Shade trees are especially subject to damage. 
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