Insects Bred from American Larch 13 
the weather was too dry, water was occasionally sprinkled 
on the pieces of wood to prevent conditions from becoming 
too unfavorable. In any event the conditions were doubtless 
as uniformly favorable as they would have been had the 
material remained undisturbed in its natural environment. 
The various breeding cages were examined daily and all 
insects which had emerged were kept separate with full data. 
As the exact source of each insect emerging was scrupulously 
recorded it was an easy matter later to find the various sorts 
of insects associated in the same pieces of wood and im simi- 
lar wood from other trees or regions of trees. By supple 
menting such data with later study of the wood it is often 
possible to secure evidence to establish either absolutely or 
probably that certain insects bear the relation of parasite 
and host to each other. Whenever practicable the exit hole 
made by an emerging insect was found and marked with the 
same lot number as the insect which came from there. Later 
this burrow was opened and the character of the larval mine 
and pupal chambers studied. Specimens of several sorts of 
larvee were also taken at intervals; and, by a later careful 
comparison of such records of adults, burrows and larve as 
was thus obtained, it was often possible to connect absolutely 
the various stages of the imsect and the burrow it produced. 
Descrirprion or Wooptor From Wuicu THe LARCH WAS 
SECURED 
With the exception of five pieces obtained from Wanakena, 
N. Y., all of the infested larch used in this study was secured 
from near Crittenden, N. Y. Crittenden is twenty-one miles 
east of Butfalo, im the northwestern part of Erie county. 
The woods from which the larch was taken is one of con- 
siderably larger dimensions than is usually met with in that 
section. ‘The tract comprises about one hundred acres. The 
larger part of it is owned by the New York Central Rail- 
road, the rest belonging to the adjoining farms. 
The greater number of tree species in this track belong 
to the climax forest type —the principal ones being hard- 
