forest insects is mentioned. A complete list of the species known to occur in the 
United States and Canada ts available (697). 
Family Stephanidae 
Stephanids 
This small family of rather rare insects, parasitic on coleopterous and hymenop- 
terous wood borers, is represented in eastern forests by only one genus and two 
species. Adults are usually collected on dead trees harboring their wood-boring 
hosts. The adult is odd looking, having a crown of teeth on its spherical head which 
is situated at the end of a long neck. 
Family Aphidiidae 
Aphidiids 
Until recently this family was considered a subfamily of the Braconidae. It 
consists of 3 subfamilies, some 16 genera, and 114 species. Most species are 
solitary endoparasites of both larval and adult aphids. Pupation may take place 
inside or outside the mummified host. Several species have been introduced from 
abroad in biological control programs (697). 
Family Hybrizontidae 
Hybrizontids 
This small family, consisting of one genus and two species, was originally 
considered a subfamily of the Braconidae. Because of their rarity, little is known of 
their host relationships. They may be parasites of ants or aphids (697). 
Family Braconidae 
Braconids 
The family Braconidae constitutes one of the major groups of insect parasites. 
The majority of species, nearly 2,000 for North America, are parasitic in the larvae 
of Lepidoptera, but a large number are also parasitic in the larvae of several other 
orders, especially the Coleoptera. Braconid adults are seldom more than 15 mm 
long. They resemble those of the family Ichneumonidae in lacking a costal cell but 
differ in not having more than one recurrent vein. Many species pupate in silken 
cocoons on the outside of the body of the host, whereas others spin cocoons entirely 
apart from their hosts. There are from one to many generations per year, depending 
on the species. In some species the life cycle may be completed in less than 2 weeks 
(216). 
In addition to the large number of native species attacking forest insects, several 
species have been imported from abroad to parasitize important introduced pests. 
Following is a brief description of a few of these. 
Agathis pumila (Ratzeburg) was imported into the United States and Canada 
against the larch casebearer during the 1930's. It is now widely distributed through- 
out eastern Canada and the Northeastern United States and is providing a high 
degree of suppression in some areas. It has also been transferred from the Northeast 
into Idaho where the larch casebearer was first discovered on western larch in 1957. 
Genetic stock of A. pumila from Wisconsin was also released and established in 
Oregon and Washington in 1973 and 1974 (/047). Winter is spent in the larval stage 
within the host and there is one generation per year. 
Meteorus versicolor (Wesmael), a parasite of the browntail moth and various 
other species of Lepidoptera, was introduced from Europe into the United States 
early in the century, and is known to have been established since 1909. It is now 
widely distributed throughout the range of the browntail moth in New England, but 
appears to be of little value in its suppression. Attempts to establish it on the satin 
moth in the Northeast have failed. It is established on the satin moth in the Pacific 
Northwest, however, where it is considered an important control factor (2/8, 328). 
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