22 Mr. R. H. Lewis on Ajjple Blight, 



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 brownness of the leaves, caused by the mining, 

 but which is by him attributed to the withering blast of an easterly 

 wind, is astounded when he perceives myriads of caterpillars swarm- 

 ing on the trees, and proceeding with alarming rapidity in their de- 

 vastating course. The fact of their mining sufficiently explains the 

 reason of their sudden appearance : 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. Various conjectures have been 

 made to explain this puzzling fact, but it is unnecessary for me now 

 to detail them. Even had the naturalist detected them in the leaA^es, 

 he would scarcely have thought them the same, their present habits 

 differing so much from those which they afterwards assume ; in 

 addition to which they are now of a yellowish colour, though they 

 become darker at each change of sldn. It is in this state that I 

 would recommend their destruction, by gathering and burning every 

 leaf which by its outward appearance betrays the internal ravages. 

 Their nests are so difficult to discover that searching for them seems 

 entirely out of the question, and I am much afraid that could any 

 wash be conveniently applied to the small twigs, whatever might be 

 sufficiently powerful to penetrate the glutinous covering, would at 

 the same time injure the tree. This, however, I leave to those more 

 acquainted with practical gardening than myself. 



The future proceedings of the insects, while they cover tlie trees 

 with their webs, have been so well described by others, and are 

 altogether so well known, as to need no description here. 



Having satiated themselves with the growing hopes of the gar- 

 dener, who endeavours, but in vain, to stop their destructive career, 

 they prepare for the pupa state by spinning strong white cocoons of 

 an ellipsoidal form. I mention this fact because an anonymous 

 writer has recently given, in a periodical work confined to our fa- 

 vourite study, an amusing though erroneous account of the habits 

 of this moth. 



In a short time they emerge from their pupte, and may be seen 

 in the evening, but more particularly in the early morning, flying 

 by hundreds round those devoted trees which are, in the following 

 year, to be the scene of similar ravages, unless circumstances for 

 which we cannot account should prevent their multiplication. 



