PEAK BORER. 7 
domen and antennae made the insects fairly conspicuous against the 
dark background of bark. The moths had to be approached warily, 
for they were quick to take alarm at any careless motions made in 
their near presence. When frightened they disappeared almost in- 
stantly and it was useless to try to follow them to another tree. In 
ovipositing the moths flew with a wavering, gliding movement near to 
the tree with the antennas brushing the bark. They alighted at 
frequent intervals and moved the tip of the abdomen back and forth 
as they crawled over the bark seeking for a rough surface or a crack 
in which to place an egg. Sometimes the entire abdomen would be 
inserted under a scale of bark, or into an opening, where it would be 
held motionless for a second while the egg was being laid. Evidently 
a female lays only one egg in a place at a time, but repeated visits of 
females to a suitable location result in the eggs being grouped to- 
gether by the end of the oviposition season. In one instance seven 
eggs were found in a heap at the bottom of a crack in the bark. The 
eggs are so small and inconspicuous that it is next to impossible to 
find them on the bark, even with an ordinary hand lens. Specimens 
of bark on which female moths had been seen to alight, but on which 
no eggs could be found in the field, were taken to the laboratory and 
placed under a microscope, where numerous eggs were easily dis- 
covered. 
CANNIBALISTIC TENDENCIES. 
In several instances a number of larvae of different sizes were col- 
lected in the field and placed with pieces of live apple bark in large 
vials to be taken to the insectary. Sometimes the larvae would be 
retained in the vials for several days. In all such cases it was found 
that the larger larvae would kill and devour the smaller. That canni- 
balism is sometimes practiced under normal conditions is indicated 
by the fact that the larvae are always found occupying burrows inde- 
pendent of one another, although eggs are frequently laid in groups. 
In a few cases small larvae were found devouring their own kind on 
the trees. 
NATURAL ENEMIES. 
It is a. common thing to find burrows of the pear borer that have 
been opened and the occupants removed by woodpeckers, although 
the species of bird responsible has not been observed. The larvae and 
pupae are rather extensively attacked by parasites, perhaps 50 per 
cent of them being destroyed in this way. Table III gives a list of 
the hymenopterous parasites reared by the writer from the pear 
borer. In addition to the species named in the table, there is a 
record of another parasite, Stilbopoides sesiavora Roh., 5 reared from 
this host. 
; Rohwee, S. A. Descriptions of new parasitic Hymenoptera. In Proc. Ent. Soc, v. 15, p. 180- 
188, 1913. 
