612 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
Famitry EURYTOMIDAE 
Probably no other family of chalcids exhibits so wide a diversity 
of habits as is met with among the members of the Eurytomidae. 
Many species are phytophagous. Other members of the family live 
in the nests of bees and wasps or are parasites of gall-forming Diptera 
and Hymenoptera. <A few are egg parasites of Orthoptera, while 
several species of Hurytoma appear to be almost ubiquitous in their 
selection of hosts. 
Eurytoma pissodis Gir. is one of the most important parasites of 
the white-pine weevil (Pissodes strobi) throughout the entire range 
of its host, and parasitization as high as 50 percent has been recorded. 
Taylor (406) found 6 percent parasitization in about 3,000 weeviled 
white-pine leaders. He found parasitization limited almost entirely 
to weevils within leaders from 14 to % inch thick, and he believed 
this was due to the fact that the parasite’s ovipositor was too short 
to reach weevils in thicker stems. The adult is from 14 to 14 inch 
long, and is black, dull on the sculptured thorax but glossy on the 
polished abdomen, with conspicuous red eyes. It overwinters as a 
prepupa within the pupal cell of the host larva. Transformation 
takes place in the spring, the adult parasite cutting its way out through 
the xylem of the weeviled leader. Adults emerge shortly before the 
Pissodes larvae complete feeding, which may be from the middle of 
May until the middle of July, depending on the season. The female 
oviposits either through the stem or through the host larva’s entrance 
shaft. The egg is laid on the full-grown host larva within its pupal 
cell. The parasite larva feeds externally, becoming full-fed in about 
10 days. Practically all the parasites complete only a single genera- 
tion, but about 4 percent transform to adults in August. These indi- 
viduals do not find the Pissodes larvae in a stage suitable for para- 
sitization, so they possibly complete another generation on some other 
host. 
Famity PERILAMPIDAE 
The Perilampidae make up a small family. The North American 
species, the habits of which are known, are secondary parasites, at- 
tacking Diptera, Hymenoptera, and Neuroptera, but certain species 
from Australia are phytophagous. 
Perilampus hyalinus Say is a common species throughout the United 
States. It is a secondary parasite of numerous Lepidoptera, develop- 
ing at the expense of many species of Tachinidae and Ichneumonidae. 
Smith (383) reported on its biology as a secondary parasite of the 
fall webworm (Hyphantria cunea). The adult ranges from about 
4, to 46 inch long. It is bright, metallic, bluish green. Like all 
members of the family, it is characterized by a large thorax and small 
triangular abdomen. It has a remarkable history in that its egg is not 
laid on or in the host, but at some distance, and in all probability on 
foliage, as are those of other Perilampus species. 
The first instar is a minute, mobile larva, which has been called a 
planidium. It crawls to a caterpillar and bores its way into the body 
cavity, there swimming about freely until the larva of a primary para- 
site, either hymenopterous or dipterous, is found. It then bores into 
its true host, where it remains quiescent until the primary parasite 
larva is full-fed and has made its exit from the caterpillar to pupate. 
