22 College of Forestry. 
they apparently act as scrapers. The fore legs were occa- 
sionally used in helping free the mandibles of frass but were 
usually not needed. Ordinarily they were braced against 
the sides of the burrow with the base of the femur fitting 
snugly in the smooth surfaced groove (Fig. 1, 2) at the 
ventro-lateral sides of the prothorax. 
At the end of two hours work the burrow was advanced 
far enough so that the prothorax was two-thirds covered. 
The middle legs which now were nearly at the level of the 
surface, were still used in gripping the bark. The hind legs 
were flexed against the body and were used only occasionally 
in aiding in the disposal of the frass. At about this time 
the specimen was observed to defcecate for the first time 
and this was continued at intervals of from two to thirty 
minutes from this time on. The foeces was eylindri eal, 
brownish, translucent and quite sticky as was shown by the 
fact that it adhered to the stiff bristles surrounding the anus 
and later adhered to the pile of frass surrounding the en- 
trance to the burrow. 
The condition of the bark was now apparently more 
favorable, but the specimen experienced considerable difh- 
culty in gouging out the bottom of the burrow. This me- 
chanical difficulty was overcome by making the burrow 
wider just under the bark (Fig. 8), thus allowing space for 
his prothorax while his jaws were brought into play upon 
the center of the bottom. In this process considerable range 
of motion was shown at the juncture of prothorax and 
mesothorax. On pushing with his middle legs, the posterior 
part of his body was forced up so that the elytra nearly 
touched the prothorax and on pulling, the body was flexed so 
that the anterior part of the mesothorax was pulled out of 
the prothoracic collar to such an extent as to expose con- 
siderable of the membranous connecting part. 
In order to see just the character of the burrow at this 
stage, the specimen was removed. The burrow was approxi- 
mately the shape shown in Fig. 8. On attempting to return 
him to the burrow, he would not resume work but wandered 
off over the bark moving in a jerky way and apparently 
irritated at the rough handling. 
