160 
Psyche 
[June- August 
when gravid. The prepupae left in the tubes eventually passed 
through the same stages of infestation. The apparently un- 
infested prepupae are of a creamy white appearance and often 
move slightly. No matter how frequently they were transferred 
to sterile tubes during January and February, all of them were 
destroyed. Thus, of several hundred prepupae, only five reached 
the pupa stage and these, with one exception, died, covered 
with mites. The exceptional one attained the adult stage but 
did not live long enough to disengage the pupa skin completely. 
It is probable that Pediculoides was able to infest a prepupa 
for several days without any evidence of its presence, since, al- 
though each prepupa was brushed and examined carefully before 
isolation, the mite invariably appeared. It is also probable that 
a prepupa, at the time of its transference, might have had one or 
several mites upon its surface which survived the brushing and 
escaped notice. That this acarid could remain unnoticed, is at 
least possible, because of its minute size, pale color, and semi- 
translucency when young. It is also possible that it may pene- 
trate into the spiracles of the prepupa. 
Some other parasites of the white pine weevil, namely 
several Braconids that pupate in pupa cases or cocoons in the 
larval chambers of the weevil, were not attacked by Pediculoides , 
although they were reared throughout in unsterilized tubes. 
Whole sections of twigs were in the tubes in this case ; much frass 
and decaying bark was present, yet the emergence percentage 
was very high. In the material dissected, however, many intact 
cocoons were found which were shrivelled and which showed that 
they had been destroyed by some agency which may have been 
the mite. In other weevil larval chambers, groups of mites were 
found with remains sufficiently indefinite to defy analysis, al- 
though very probably, they were examples of Eurytoma pissodis 
which were destroyed under natural conditions, since abundant 
evidence, such as no weevil emergence hole in the wood, the size 
of the twig, and contiguous Eurytoma prepupae, pointed that way. 
No clear cut case of mite destruction of weevil larvae was ob- 
served, though this proves nothing, since, at the time of dissec- 
tion, at least three months had elapsed since the weevil larvae 
were in the shoots. Several cases of mite destruction of unde- 
