116 
PINE. 
$ 
trees attacked I found unfinished galleries quite full of resinous secre¬ 
tions, and containing the dead bodies of the male and female insects, 
which had doubtless been drowned or suffocated by the resinous 
exudations.” * 
Dr. Somerville kindly favoured me with a piece of Larch bark con¬ 
taining several good examples of the mother galleries of the Pine 
Beetle, the H. piniperda, one of which I had most carefully figured, 
so that the wood engraving (p. 115) gives a precise representation of 
it, both nat. size and magnified. These figures show how the flow of 
turpentine, now hardened into an irregular coating, has in this instance 
stopped development of the little maggots, although, if carefully 
examined, the figure shows a row of little scallopings or niches along 
the side of the gallery from which, under favourable circumstances, 
the larval galleries would have been commenced. It will be observed 
that Dr. Somerville draws attention markedly to the presence of sap 
in active flow being a powerful agent in prevention of attack, even to 
the extent of some of the galleries being “ quite full of resinous secre¬ 
tions, and containing the dead bodies of the male and female insects.” 
This point of resinous flow demonstrably as well as theoretically 
stopping attack was of such practic al interest, that I wrote further 
about it to Dr. Somerville, who kindly replied to me (9tli Dec.):— 
“ I delayed answering your letter till I had made another 
examination of the Larch trees, and I am now able to answer your 
questions fully. The trees which were attacked by H. piniperda were 
taken possession of by great numbers of this insect, which laid its eggs 
in little niches as usual; these in due course hatched out, and the 
larvaB proceeded to eat into the bast, but the resin had proved too much 
for them, for in no case (at least in no case that I have observed) did 
they develop into beetles. 
“ Whether it is possible for this insect to use Larix as a breeding 
place successfully or not remains to be shown. Middendorff in his 
‘ Siberische Beisen,’ says the Larches were quite full of the galleries 
of H. piniperda , but he does not say whether these were mother or 
larval galleries.”—(W. S.) 
These observations appear to me to be very interesting, not only 
as chronicling a first record of infestation in a new geographical 
locality, but also as a reason why it is very unlikely to appear in the 
phase injurious to the living tree. Also it shows us the perfect 
correctness of the principle we work on to keep the attack of the Pine 
Beetle, H. piniperda , in check on the plantations of Scotch Fir, to 
which it is mainly (and often very seriously) injurious. 
It frequents for breeding purposes felled trees, or broken branches, 
* “ Larix europaa as a breeding place for Hylesinus piniperda ,” by William 
Somerville, D.CEc., B.Sc. (Bead July 7, 1890.) 
