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tliat the state of the trees, scarcely bears out the author's own conclusion as to Scolytus 

 attacking sound trees, since fifteen out of the eighteen were manifestly attacked by 

 the most deadly enemy that a timber tree can possibly have : and to a superficial 

 observer, I purposely repeat this qualifying expression, nothing can present a more 

 sickly or abnormal appearance than a tree, the solid timber of which is riddled 

 through and through by the enormous lawse of Cossus ligniperda : such trees, with 

 or without the smaller pest, I should have unhesitatingly pronounced in an unhealthy 

 state. When Captain Cox favours us, as I doubt not he will, with an explauatii)n of 

 this apparent inconsistency, arising probably from some acciilenlal oversight or trans- 

 position of words, may I ask him to reexamine the larvae which he denominates those 

 of Cossus ligniperda, and which had so severely injured the fifteen trees under con- 

 sideration ; because I never happened to find thai insect feeding on elm, and had not 

 the statement been made by an entomologist who possesses an unusually extensive 

 knowledge of the larvae of our British Lepidoptera, I should have fancied that 

 the trees were dying from some other and undiscovered cause. One other slight diffi- 

 culty occurs to me which will, doubtless, be removed without causing any additional 

 or unnecessary trouble to Captain Cox. Seeing that the larva of Cossus mines 

 the solid wood, and not the bark, except in its very juvenile state; and seeing that the 

 fifteen Cossus-mined trees completely recovered after their outer bark had been merely 

 draw-shaved, how is it to be explained that this simple external process affects 

 the deadly Cossus deep in the interior? The author has not explained this, 

 probably concluding that entomologists were more intimately acquainted with the 

 reciprocal offices of bark and solid wood, than I fear is the case. I trust tliat 

 these queries, unimportant in themselves, will not be deemed irrelevant, but will 

 acquire some importance from the acknowledged importance of the subject; I hope 

 they will induce Captain Cox to enrich our ' Proceedings' with a second paper still 

 more explanatory than the first. As an observation on Scolytus, quite independent of 

 the paper to which I have been alluding, it is rather interesting that in the two great 

 London colonies of this insect, Greenwich Park and Camberwell Grove, its advent 

 dated two years subsequently to the introduction of gas, and its ravages have not yet 

 extended beyond the reach of the gas influence : that gas has an injurious effect on 

 elms is a self-evident fact, so probably have all gases evolved by combustion in facto- 

 ries, since we always see elms in manufacturing cities losing their leaves six or seven 

 weeks earlier than in the country : in this weakened state trees are particularly obnoxious 

 to the attacks of insects, and about London elm trees are generally infested with 

 the larvae of Scolytus destructor and Zeuzera iEsculi. I am well aware of the alleged 

 fact of the trees in the Hartz forest and elsewhere in France and Germany being 

 destroyed by Scolytus, still the coexistence of elm failure and gas-lights must remain 

 an indisputable fact, although at present a fact from which no general conclusions can 

 be safely drawn.'' 



Mr. Westwood observed, with reference to the latter part of Mr. Newman's paper, 

 that the Scolytus was abundant in Christ Church Meadows, Oxford, far away from 

 gas-lights." 



