162 
Psyche 
[June-August 
straightening within a minute, and then repeated this behavior 
several times within an hour. The females, which form a large 
majority of the individuals apparently tend to remain attached 
to the original puncture till distrubed, their abdomens swelling 
to a size 10 to 50 times that of the cephalothorax. If the prey is 
fresh, the mites are aided in their attachment by the adhesive 
quality of the fluid that issues from the punctured body. If 
brushed off they will puncture in the next place at which contact 
is established, although their mobility decreases, of course, with 
their growth. As seen in the figure, the mites appear as globular 
excrescences upon the surface of the infested larva or pupa, since 
the cephalothorax is hidden by the enlarged abdomen and may 
be more or less intruded into the body of the host. 
Control of Pediculoides, natural or otherwise, has not been 
worked out and references to its control are very rare in the liter- 
ature. That it has some natural enemies seems probable, be- 
cause without some check, and with its capacities for increase 
and for destruction of insects, it would soon become more 
conspicuous. Under natural conditions in the white pine leaders, 
however, this acarid is not found in every part of the shoot, and 
in this fact lies the explanation of how a certain number of 
parasites may survive. 
In conclusion, I offer the suggestion that Pediculoides ven- 
tricosus is more of a factor in economic entomology than is 
realized. Beneficial in checking cereal insects, it is not a com- 
pletely welcome agency there, as it may seriously impair the 
efficiency of the harvest hands and other grain workers. Apart 
from this, it probably does more harm than good, all things 
considered, as it destroys parasites that have many times its 
own predatory power in controlling injurious insects. A com- 
pilation of tests for the purpose of ascertaining whether the 
mite prefers parasites in dead wood and straw, or whether it 
prefers wood-borers and stem-borers in material which is fresher 
or not entirely dead, and has less decaying bark, would be in- 
teresting. 
Abstract. 
The mite, Pediculoides ventricosus Newport, is beneficial in 
destroying cereal insects, notably Isosoma species, and others. 
