Figitidae, Eucoilidae, Alloxystidae, and Cynipidae (697). The liopterids are mostly 
exotic, and their habits are unknown. 
Family Ibaliidae 
Ibaliids 
Members of this family are all parasitic on horntails of the family Siricidae. At 
least four species are recorded from the Eastern United States—J/balia anceps Say, 
I. leucospoides ensiger Norton, 1. maculipennis Haldeman, and I. scalpellator 
Westwood (697). 
Ibalia scalpellator, a common species in the Eastern United States and south- 
eastern Canada, is a parasite of pigeon tremex. The adult is marked with a yellow 
and dark-brown pattern, has two conspicuous dark-brown to black bands on the 
forewings, and is about 12 mm long. 
Family Figitidae 
Figitids 
This family of 60 North American species is represented in eastern America by 
about 30 species. The majority are parasitic in dipterous puparia; a few are parasitic 
in the cocoons of chrysopids. 
Family Cynipidae 
Cynipids or Cynipid Gall Wasps 
This family of several hundred species consists mostly of species that induce 
galls on their plant hosts in which they live and feed during the larval stage. Many 
others live as inquilines in galls produced by other insects. The adults are small to 
extremely small and usually black. They are distinguished by the abdomen that is 
oval, shining, somewhat compressed, and almost covered by the first tergite. Many 
gall-forming species produce two quite different generations per year. One genera- 
tion develops during the summer in one type of gall. Adults appear in the fall and 
consist entirely of parthenogenetic females. Eggs laid by these females give rise to 
larvae that induce 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 induce galls on 
oaks and are confined to them (668). There are 717 species listed as occurring in 
the United States and Canada, 76 percent of which induce galls on oaks. 
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 that induce large irregular galls on the smaller branches are capable of 
causing injury (fig. 201). Infested branches may be disfigured or even killed; 
occasionally entire trees are killed. On the other hand, galls induced by certain 
other species are economically valuable—some have long been used in the man- 
ufacture of ink and in dyeing and tanning, others serve as a source of winter food 
for bees. One, a deciduous oak gall, is occasionally abundant enough on black oak 
in Missouri to be used as food for hogs, cattle, sheep, turkeys, and chickens (667, 
669). Some of the more common and important gall-inducing species are discussed 
below. 
Callirhytis floridana (Ashmead) occurs from Virginia to Florida and Missouri 
and Arkansas. It induces slender, elongate swellings from 12 to 75 mm long on 
branches close to the ground of Chapman, post, and sand post oaks. Large areas of 
sand post oaks were nearly all killed during an outbreak in eastern North Carolina 
(669). 
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