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to effect this they mine into the leaves, eating the 

 cellular tissue only, and leaving the epidermis un- 

 touched. Having acquired sufficient strength to 

 withstand the vicissitudes of the atmosphere, and to 

 devour the epidermis of the leaves, they make their 

 way out ; and the anxious gardener, who has hitherto 

 only observed the browness of the leaves caused by 

 the mining, but which is by him attributed to the 

 withering blast of an easterly wind, is astonished when 

 he perceives myriads of caterpillars swarming on his 

 trees, and proceeding with alarming rapidity in their 

 devastating course. The fact of their mining suf- 

 ficiently explains the reason of their sudden appear- 

 ance : it shows how one day not a single caterpillar 

 may be visible on the trees, and the next they may 

 be swarming with larvae of so large a size as to rebut 

 the idea of their having been recently hatched. For 

 the destruction of these insects, various plans have 

 been recommended. Mr. Major says that nothing 

 more is required than the application of strong soap- 

 suds forcibly applied with the engine, so as to break 

 the web, that the suds may reach the insects. Where 

 the trees are not much infested, gather the webs, in- 

 cluding the caterpillars, by hand, and destroy them 

 in any way most convenient. Care should, however, 

 in these cases, be taken to kill, and not merely to 

 disturb, the caterpillars. Mr. Lewis suggests the 

 picking off and burning of the leaves whilst the cater- 



