24 College of Forestry. 
burrow. He would often partly rotate in the entrance, try- 
ing apparently to arrange the pile of frass more securely. 
As the specimen could not be induced to use other methods 
of disposing of his chips the frass was removed by blowing 
and other experiments were tried. 
Response to Liaur.— Concentrated light from a tungs- 
ton bulb was directed into the burrow by means of a bulls eye 
condenser. ‘The specimen had been hard at work, but imme- 
diately desisted and remained motionless for half a minute, 
when he resumed work as before. A small ruler was then 
passed rather slowly back and forth between the condenser 
and the burrow producing a moving shadow. Only the end 
of his body was visible, but he immediately backed upward 
until the entrance was completely blocked by the ends of his 
elytra. For the first few times this experiment was re- 
peated he responded in the same manner, but thereafter he 
would pay no attention whatever to either a moving or a 
stationary shadow.— In nature a passing shadow might mean 
danger from predaceous or parasitic enemies or it might be 
made by a branch waving in the wind. 
Response to Mrcwanican Srimvit.— Response to me- 
chanical stimuli was then tried. The entire limb was jarred 
by tapping it smartly. He paid no attention whatever, but 
continued his work. Inserting a needle into the bo the 
stiff hairs at the end of the elytra were touched as gently as 
possible. He immediately responded by backing upward and 
completely blocking the entrance of the burrow with the 
posterior end of his body, arranging himself in such a way 
that the declivity of the elytra armed with the three pairs 
of spines was on a line with the surface of the bark as shown 
in Figs. 13, 14. If when stimulated he happened to be work- 
ing with back downward, as in Fig. 11, he would back out 
as shown in Fig. 12, but would immediately revolve so that 
the greatest possible part of the opening was closed by the 
hard spiney elytral declivity (Figs. 15, 14). It is apparent 
that in the position shown in Fig. 12, the insect would be 
much more susceptible to attack than in that shown in Figs. 
18 and 14. It is worthy of note that the entrance burrow 
