2(52 [October, 



and that, therefore, it could scarcely be resplendellum. Mentioning 

 the matter to Mr. Stainton, he wrote back that he thought it had been 

 already worked out years ago in the " Intelligencer," and the insect 

 proved to be Coleopterous. 



Still, as he could not put his hand on the article, there was room 

 for doubt. Nevertheless, a season or two was allowed to pass without 

 pursuing the subject. But, in the summer of 1889, I took up the 

 question in earnest, though not in the most sanguine of moods, either 

 as to what I should find, or whether, indeed, I should find anything at 

 all, for, as the larva would not be likely to stay long in the leaf before 

 cutting out its case, and dropping to the ground, the chances of 

 detecting it would be small. However, difficulties often vanish when 

 they are approached, and the collection of the unknown birch miner 

 proved to be far easier than was anticipated. It is well known that 

 most larva? that live within growing tissues produce distortion of some 

 kind or other in the tissue, by which their presence may be known. 

 And so, the larva under discussion, being no exception to the rule, causes 

 a slight general thickening for two inches more or less at the end of the 

 shoot, quite sufficient to enable one with a little practice to distinguish 

 it from the natural shoot, which tapers gracefully. The existence of 

 so good a clue was, indeed, fortunate, because, as I afterwards learnt 

 that the larva only spends a few hours in the leaf, and these few hours 

 almost invariably at night-time, collecting it by the leaf would have 

 been utterly hopeless. 



The first larva was found on July 11th ; at that time no leaves 

 with the cases cut out could be peen, but from the middle of the mouth 

 onward, vacated mines, as shown by the leaf, grew more and more com- 

 mon, until at the end of the month the search, being no longer 

 profitable, was given up. I obtained altogether from the collected 

 twigs eleven or twelve cases, similar in shape and size to those of 

 resplendellum, from which five moths were bred this summer. The cases 

 were kept out of doors all the winter, and it was somewhat singular 

 that only those produced the moth that were lying loose on the ground, 

 whilst all those that had attached themselves to the birch twigs or to 

 the sides of the vessel, and seemed more favourably situated, were 

 unfruitful. 



The mine is long for so small an insect, and measures from three 

 to four inches before it enters the terminal leaf of the shoot, from the 

 outside edge of which, close to the insertion of the stalk, or from 

 further on in the centre, the case is cut. It commences near the surface 

 of the woody axis, keeping in that tissue for about three quarters of an 



