Plate VI. 
Fic. 15. Burrows of Phymatodes dimidiatus in trunk of 
larch. Near the center can be seen the complete larval bur- 
row, the entrance to the pupation chamber and the exit hole. 
The entire burrow is relatively short, as would be expected 
of a one-year form. Reduced to about two-thirds natural 
size. 
Fie. 16. Burrow made by the larva of Monohammus 
scutellatus in white pine. All of the larval work cannot be 
seen, but characteristic points are shown. Note that the 
part of the burrow adjacent to the chamber in the wood used 
for retiring, hibernation and pupation has been kept free of 
frass, while much of the rest is packed full of the character- 
istic “ sawdust” like detritus. Note also the oval opening 
leading to the pupation chamber (below) and the nearly 
exactly cireular exit opening (above). Reduced to slightly 
less than one-half natural size. 
Fre. 17. Thin-barked limb of white pine showing where 
the adults of M. scutellatus have fed upon the thin smooth 
bark. At various places in the smoother areas of the bark 
can be seen the work of the mandibles of the beetles. The 
females oviposit in such areas and the several small white 
spots in these areas indicate “ ventilation openings ” through 
which the newly hatched larvee have extruded the white frass. 
These “ ventilation openings” of the very young larve are 
the openings made by the ovipositor of the female, which 
have been enlarged and utilized by the newly hatched larva. 
Reduced to about one-half natural size. 
Fic. 18. Portion of the trunk of a small larch sapling, 
showing the burrow of Leptostylus sea-guttatus. ‘The entire 
burrow, including larval mine, entrance to pupation chamber 
and exit hole, is shown. This being a two-year form, the 
burrow is relatively quite long. Slightly more than one-half 
natural size. 
