32 College of Forestry. 
and one female each, one burrow by a male and two females 
and one burrow by a single female. This latter burrow, al- 
though longer than any of the rest, contained nothing similar 
to a nuptial chamber and from evidence furnished by other 
cases was probably a continuation of an entrance burrow 
made by a male and later abandoned. Newly infested limbs 
brought in from out doors, showed also that where nuptial 
chamber was occupied by only one specimen, this was invar- 
iably a male. Thus the evidence indicating that the male 
constructs the entrance gallery and nuptial chamber unaided 
seems absolutely conclusive for this species and without a 
reasonable doubt such is the habit in all polygamous bark 
beetles. 
Marine Hasrrs.— Concerning the details of the mating 
habits of P. hopkinst very little was learned from direct 
observation. Copulation was observed in only one instance 
although several burrows were kept under frequent observa- 
tion with the view of settling several obscure points. It is 
therefore known that copulation occurs in the nuptial cham- 
ber, but whether or not it may also take place outside of the 
burrow is not known, although the tenacity with which the 
male remains in his burrow would seem to indicate strongly 
that such is not the case. It is also not certainly known 
whether a female must be fertilized more than once or not, 
although evidence that frequent copulation such as has been 
found to occur in Ips typographus by Niisslin (1907) and 
in Phloetribus liminaris by Gossard (1913) is not neces- 
sary in P. hopkinsi, seems fairly conclusive. 
The most complete observations upon the later history 
of the brood-burrow and the periods of time which the 
various stages last were made upon ene burrow designated as 
“burrow H” in the writer’s notes. Burrow H was started 
on March 15th. The male constructing it was not particu- 
larly industrious, as was shown by the small quantity of 
frass cast out and also by the fact that the nuptial chamber 
was not completed at the end of five days. At this time 
it was occupied by a male only and the flap of bark loosened 
in order to examine the progress of the work, was success- 
