88 College of Forestry 
S. barbatus in ovipositing in larch chooses either trees 
which are dying or which have recently died, or living trees 
from which part of the bark has been peeled (this latter 
being in line with its common name of “ blazed tree borer’). 
Occasionally oviposition occurs in living trees — most often 
in injured or dead parts of the bark. In several cases adults 
emerged from recently dead larch the same year as Poly- 
graphus and Eccoptogaster — indicating that it must have 
entered this material a year earlier than did the scolytids, 
while the trees were still alive. Usually only the lower trunk 
is attact, but several specimens have been bred from the 
trunk up among the limbs as muchas thirty feet from the 
ground. 
The larval stage of S. barbatus is spent nearly entirely in 
the sapwood. As soon as they are hatched, the larvee bur- 
rows from the bark into the sapwood and continues mining 
this part of the tree for two seasons. The larval burrows 
are very irregular in their course, winding this way and 
that and showing no discoverable pattern. It is noticeable, 
however, that a ‘greater part of the length of the burrow is 
in the soft spring wood and it will often extend for several 
inches, either longitudinally, circumferentially or diagonally, 
without leaving a single ring of growth. The burrow is oval 
in cross section, the long diameter, which is about twice the 
shorter diameter, being tangential, 7. e., confined to one layer 
of “spring wood.” The entire larval mine is packed full of 
a very fine dust-like frass. 
Before transforming to the pupa the burrow is extended 
by the full-grown larva, which reaches a length of 25 mm. 
to a level not more than a half inch from the bark and a 
slightly enlarged chamber is here constructed parallel to the 
surface of the sapwood. However, before transforming, the 
burrow is extended to the surface of the sapwood, so that 
the adult may emerge without having to bore through the 
wood. Field notes of the senior author, dated Cranberry 
Lake, June 10, 1915, read as follows: “ Numerous adult 
beetle and two larve taken from sapwood of a small dead 
hemlock. Adults were taken from chambers extending 
