sawfly, which it parasitizes heavily at times. It has not been 
recovered from the spruce sawfly in the United States. 
Exenterus abruptorius (Thnb.), an important parasite of the 
European pine sawfly in Europe, was imported into Canada during 
the thirties against the European spruce sawfly and European 
pine sawfly. Colonies were later made available for release in the 
United States. Recoveries were made from the pine sawfly sev- 
eral years after liberation in New Jersey. 
Mesoleius tenthredinis Morley was imported into Canada from 
England in 1910-11 and liberated against the larch sawfly. A 
colony was also released against the sawfly in the Great Lakes 
region. It became established and for many years effected con- 
siderable control. Gradually though, the host developed an im- 
munity to the parasite in many portions of its range, thereby 
greatly reducing its effectiveness. So far, this immunity does not 
seem to have developed in the more easterly infestations into 
which the parasite has spread. 
Pimpla turionellae (L.), a European parasite of the pupae of 
many Lepidoptera, was imported against the European pine shoot 
moth during the thirties. It has not been recovered in the United 
States but is apparently established in southern Ontario. 
Temelucha interruptor (Grav.) was imported from England 
and Europe against the European pine shoot moth during the 
thirties. It became established and was recovered in Connecticut, 
New Jersey, and southern New York in 1937. Ten years later, 
however, it had almost disappeared, being collected at only one > 
point in Connecticut. 
Eastern forest insects also are attacked by numerous native 
species of ichneumonid parasites. Itoplectis conquisitor (Say) 
parasitizes a tremendous number of species, and is especially 
important. I. 4-cingulatus (Prov.) and I. viduata (Grav.) also 
attack a great many species. Megarhyssa lunator (F.) is a con- 
spicuous parasite of horntail larvae. The female is equinped with 
an extremely long ovipositor which is used as a drill for laying 
eggs in horntail larval galleries deep in infested wood. The ovi- 
positor often becomes caught in the wood and the female, unable 
to escape, dies. 
SUPERFAMILY CHALCIDOIDEA 
This superfamily contains more species than any other suver- 
family in the order Hymenoptera. It contains, among its families, 
probably a majority of all entomophagous insects, with an ex- 
tremely wide range in form, habits, host preferences, and host 
relationships. These comprise the majority and are mostly bene- 
ficial, but there also are a number of phytophagous species, many 
of which are economic pests. The species occurring in the United 
States and Canada are divided into 21 families and more than 
460 genera (588). 
Practically all of the more common orders of insects serve as 
hosts for the parasitic and predacious members of the Chalci- 
doidea, with the Lepidoptera, Diptera, Coleoptera, and Homoptera 
being preferred. The majority of the injurious tree-infesting 
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