616 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
lic, greenish-blue sheen, and with pe to dark-brown legs and anten- 
nae. It ranges from about %4¢ to 4% inch long, depending on its host 
and the number of adults emer ging. Itisa “prolific species. Under 
laboratory conditions as many as 389 eggs were laid by a single female. 
They are deposited externally on the parasite larva in its cocoon. Al- 
most always several eggs are laid in one cocoon, although no more 
than 2 or 3 eggs are laid duri ing one insertion of the ovipositor. The 
larvae feed eregariously. As: many as 14 adults have been reared 
from an A panteles cocoon and as many as 40 from a cocoon of Diprion 
hercyniae. Development requires from 17 to 34 days, depending 
lar gely on temperature, and as many as 5 generations were reared 
at the labor: atory under outdoor temperatures. The winter is spent 
as a full-grown larva within the host cocoon. 
In common with many other parasites Dibrachys adults often feed 
at the puncture holes made by their ovipositor. Feeding may be 
either direct or by means of a tube constructed with the ovipositor 
from the larva to the outside of the cocoon, through which the larval 
juices are sucked. This feeding is probably supplemental to feeding 
on honeydew and other sweet juices, but it may be an important source 
of nitrogenous material essential to ege laying. A great many host 
larvae that are not parasitized are killed j in this manner. 
Schizonotus sieboldi (Ratz.) 1s a primary parasite of the imported 
willow leaf beetle (Plagiodera versicolora) and some other closely 
allied chrysomelids. It is well distributed throughout the eastern 
half of the United States and apparently is present wherever P/lagi- 
odera occurs in this country. Dowden (1/37) reported high percent- 
ages of parasitization over a 3-year period in the vicinity of Boston, 
Mass., but believed about the same intensity of host infestation was 
maintained during that time. The adult is from 4%, to 4%» meh 
long, metallic green, with darker highly polished abdomen, and yellow 
legs. The winter is spent as an adult. Activity is resumed in the 
spring, and eggs are laid on the first host pupae appearing in the 
field. Thisis about June 10 in Massachusetts. The eggs are laid singly 
on the venter of the pupa, and one female laid as many as 424 eggs 
under laboratory conditions. The parasite larvae feed externally, and 
an average of 2 parasites develop per pupa. About 15 days are re- 
quired from egg deposition to adult emergence. Two, and sometimes 
three, generations develop during the summer. 
Famiry EULOPHIDAE 
The Eulophidae make up a very large family, and many are minute 
insects. They attack practically all orders of insects, but certain 
subfamilies and smaller groups frequently attack only closely related 
hosts. The Eulophinae are principally primary or secondary para- 
sites of leaf miners. The Tetrastichini, on the other hand, attack a 
wide variety of hosts. 
Chrysocharis laricinellae (Ratz.) (fig. 189) is an important para- 
site of the larch casebearer (Coleophora laricella) and of Phyllotoma 
nemorata, the birch leaf-mining sawfly, in Europe. It has recently 
been successfully introduced into New England as a parasite of both 
these pests, and Dowden (139) gave an account of its biology as a para- 
site of P. nemorata. The adult is from 2 to 3 mm. long, bright, me- 
tallic green with pale-yellow legs. Females oviposit in the body of 
