The genus Monodontomerus contains several important parasites of various 
species of Lepidoptera and sawflies. M. dentipes (Dalman), a European species 
which probably entered this country with its European host, the introduced pine 
sawfly, is now widely distributed in southeastern Canada, in the Northern States 
from Maine to the Lake States, and in North Carolina. It is not only an effective 
parasite of the introduced pine sawfly, but also an important parasite of several 
other sawflies attacking conifers (fig. 200). It spends the winter as a prepupa inside 
the host cocoon. Adults appear over a fairly long period in the spring and lay their 
eggs through the host cocoon, depositing several upon the prepupa. There are 
probably two generations per year in the North. 
F-531263 
Figure 200.—Monodontomerus dentipes ovipositing in a 
cocoon of the introduced pine sawfly. 
Monodontomerus aereus Walker was introduced to New England from 1906 to 
1910 against the gypsy and browntail moths. It was released originally as a primary 
parasite but is much more common as a hyperparasite, attacking both hymenop- 
terous cocoons and tachinid puparia. It is also parasitic on the whitemarked tussock 
moth and the eastern tent caterpillar. 
Other species of Monodontomerus recorded as parasites of important forest 
insects in the Eastern States include M. indiscretus Gahan—on birch leafminer; M. 
montivagus Ashmead—on spruce budworm; and M. minor (Ratzeburg)—on east- 
ern tent caterpillar, cecropia moth, and spruce budworm. 
Family Pteromalidae 
Pteromalids 
The family Pteromalidae is the largest in the superfamily (129 genera and 395 
North American species), and its members act as parasites or hyperparasites of 
almost all orders of insects (697). The adults are minute, black or metallic-green or 
bronze insects. Many have a more or less triangular abdomen. 
Perilampus hyalinus Say, a common species throughout the United States, may 
act as a secondary parasite of a large number of insects in which it develops at the 
expense of many species of primary tachinid and ichneumonid parasites. The adult 
is a bright metallic bluish green and is from 2 to 4 mm long. The thorax is large and 
the abdomen triangular. More than 20 species of Orthoptera, 16 species of Lepidop- 
tera, 12 species of sawflies, and many species of ichneumonid, sarcophagid, and 
tachinid parasites are listed as hosts (974); studies of its biology as a secondary 
parasite of the fall webworm and as a primary parasite of the Swaine jack pine 
sawfly have been reported (//07, 12/1). 
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