96 College of Forestry 
obtained several specimens from twigs of Rhus glabra asso- 
ciated with the cerambycids Liopus fascicularis, Harr. and 
Psenocerus supernotatus Say and the scolytid Pityophthorus 
consimilus Lee. 
From the fact that P. dislocatus is constantly found in the 
burrow of a great variety of other insects, there can be little 
doubt that it is predaceous upon a large number of species. 
In larch it was bred from practically every lot of material 
placed in the breeding cages and therefore a list of probable 
associates in larch would include practically all of the forms 
bred from larch, including parasites and other predators as 
well as the true borers (see table on p. 38). It is indeed 
possible that this clerid may on occasion be predaceous upon 
all of these various forms. Even such forms as the larve 
of Monohammus scutellatus, which when well grown would 
conceivably be very well able to defend themselves would, 
when small, be comparatively helpless if attacked by an 
active, full-grown larva or by an adult of P. dislocatus. 
Furthermore, on account of its burrow being open from the 
time the larva is hatched, this round head would seem to be 
particularly subject to attack by predators. 
Perhaps the greatest difficulty in the way of P. dislocatus 
being freely predaceous upon all of these insects, lies in the 
fact that typically the burrows of all of the flatheaded borers 
and most of the roundheaded borers in larch are entirely 
devoid of opening to the outside (except accidental openings) 
and in the further fact that the larval burrows are filled with 
more or less firmly packed frass. Occasionally, free access 
to such larval burrows may be had, however, through the 
ege-galleries of associated scolytids, at places where these 
latter passageways are crossed by the burrows of the larger 
larvee. 
However, we are certain that in most cases P. dislocatus 
preys principally upon scolytids. It is by no means unusual, 
on opening a burrow of P. rufipennis or other scolytid, to 
find the original inhabitants all dead and the burrow uncom- 
pleted. In such cases, the remains are likely to consist of 
the mere external shell of the scolytid, all of the soft parts 
