158 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



tree. The writer suggests that the cure might be effected by 

 applying the acid to the canker without previous removal of the 

 rough exterior portion ; but he thinks it preferable to remove 

 this latter, in order that the acid may the better penetrate to the 

 root of the evil, and also that the wound may heal over the 

 quicker. He cautions persons handling the acid to exercise care, 

 and to avoid its getting on to their clothes. It would be interest- 

 ing to try this treatment in a case of larch-canker. 



A New Danger for the Larch. 



The Revue cles Faux et Forets for M-irch 1902 also contains an 

 account, by M. E. Henry, Professor of Natural History at the 

 French Forest School, of a moth (^Torlrix pinicolana) which has 

 recently commenced to do extensive damage to larch woods in 

 some parts of France. In 1900 and 1901 it completely devastated 

 the larch forests in the neighbourhood of Barcellonnette and 

 Embrun. The moth, which flies by night, attacks old trees by 

 preference. In colour it is brown, mixed with white on a grey 

 ground; it is about | inch long, and has a span of about f inch. 

 Its flight occurs during the latter half of August, but moths are 

 sometimes seen as late as the early part of October. The young 

 blackish caterpillars are hatched early in June. The full-grown 

 caterpillar is of a dark greenish colour, darker on the back than 

 on the sides; it is about ^ inch long. When the branches of the 

 trees on which they feed are shaken, they let themselves down by 

 a thread to the ground, where, under the dead needles, especially 

 in dry places, a number of chrysalises may be found, more or less 

 surrounded with needles, which are bound together by threads of 

 silk. Chrysalises are also formed in the ci'evices of the coarse 

 bark of the tree. The attack has been observed to spread to 

 spruces and Cembran pines growing among larches. 



Timber of the Silver Fiu and of the Spruce. 



Silver Fir. — The timber of this tree is here not accounted as 

 of much value, though its suitability for use in the construc- 

 tion of byres and such like buildings is recognised. The low 

 estimation in which it is held may be easily accounted for by 

 the rough quality of the trees that are usually produced in our 



