430 



penetrate the bark of a healthy rubber tree without being killed by 

 the latex, and that it is only when the laticiferous cells have been 

 previously killed by fungal hyphae, that they are able to reach the 

 wood. 



Fickendy's method of tapping Hevea bmsiliensis, which produces a 

 50 per cent, increased yield of latex by scraping the bark of the proposed 

 tapping area some time previous to tapping, has been found to induce 

 attacks by Xyleborus parvulus, and it has been experimentally proved 

 that it is the corky integument, and not the laticiferous layer, that 

 is the important protection against insect and fungus attacks. When 

 this is removed, the susceptibihty of the trees to attack is greatest, 

 being less when the green cork-cambium is left intact. The rapidity 

 of the insect attack under these circumstances is striking, borers being 

 active within four days of the treatment of the tree. 



The removal or injury of the cortical layers by fire after a spell of 

 dry weather has similar results, borers quickly attacking scorched 

 trees and causing the exudation of the latex in streams. This howcA^er 

 does not prevent the insects reaching the wood, though many may 

 be caught in the liquid. 



Dallimore (W. ). Wood Preservation. — Bnll. Miscell. Inform. Roy. Bot. 

 Gdns., Kew, London, 1918, no. 5, pp. 181-189. 



In order to preserve wood against the attacks of insects and marine 

 borers, it is necessary to make it poisonous to animal life, or to render 

 it objectionable in some other way. Highly scented woods are, as 

 a rule, less subject to injury by insects than unscented ones, and good 

 results have been obtained by dressing the latter with cedar oil. Most 

 of the substances used to protect wood from fungus attacks also 

 render it poisonous to insects, and the thorough impregnation of 

 piles and wharf timbers with heavy tar oils is the best means of 

 preserving it from the attacks of marine borers. 



Decay in furniture and other woodwork caused by the larvae of 

 beetles and other insects may be checked or stopped by kiUing the 

 larvae in situ. This may be done by heating the timber, or by soaking 

 it in a solution of carbolic acid or corrosive sublimate, or by exposing 

 it to the fumes of carbon bisulphide in a closed room. Good results 

 may also be obtained by applying the latter liquid with a painter's 

 brush, so as to fill up all the holes. Carbon tetrachloride mixed with 

 a little cedar oil or naphthaline may also be used with satisfactory 

 results, but all these substances destroy the polish when applied to 

 polished wood. 



In some tropical countries bamboos used in a natural state are 

 soon ruined by beetles, but in India they are found to be immune to 

 attack after being thoroughly soaked in water. 



Edwards (J.). Psylla sorbi, L., in Britain. — Entomologists' Mthly. 

 Mag., London, liv, no. 648, May 1918, pp. 113-114. 



The identity of the Psyllid on mountain ash, recorded by Linnaeus 

 as Psylla {Chermes) sorbi, having been in doubt, the author reports 

 having found this species at Northwich in 1910 and 1911 on mountain 

 ash. A description is given, showing the points of dift'erence between 

 it and P. mali. 



