226 [September, 



To the last the larva remains a leaf-miner, a most exceptional 

 habit for a Tortrix. So long as it is small, it can, and does occasionally, 

 leave its mine and start a fresh one, but I doubt if it ever does this at 

 large, when of good size ; and should it be in the predicament of 

 having cleared out its leaf prematurely, it tacks the point to an ad- 

 jacent one just sufficiently to allow it to burrow in from the old to the 

 mew leaf. Clearly in all this the creature has learnt, by the experience 

 of generations, to make the most of the peculiarities of the mistletoe 

 leaf, using only the thick fleshy interior for food, and leaving the 

 tough indigestible skin to serve for the walls of its chamber. A most 

 clever proceeding, that contrasts with the method Tortrix pyrastrana, 

 heparana or ribeana adopt when they select the plant, for these bring 

 their ordinary leaf-spinning habits with them, and tying two leaves 

 flat together feed upon the surfaces, in total ignorance of the trouble 

 they might save themselves by taking but a single leaf and mining 

 into its substance. 



Whatever doubt there may have been, since Mr. Barrett first 

 described the species in the pages of this Magazine, that it was merely 

 a form of the willow-frequenting Hartmanniana, can scarcely any 

 longer be entertained in the face of these facts, even though our 

 knowledge of the larva of Hartmanniana and its habits be most im- 

 perfect. It does not seem possible that a species can have two such 

 widely different food-plants as willow and mistletoe, without at the 

 same time being more or less of a general feeder, and if there is one 

 thing we do know about Hartmanniana it is that it is exclusively 

 attached to narrow-leaved willows. But allowing the possibility of 

 the two food-plants, there yet remains the difficulty of accounting for 

 its very special habits on the mistletoe, for there is nothing in the 

 willow at all analogous with the fleshy leaf of the mistletoe, and the 

 larva, ought, therefore, to treat the latter in the way that pyrastrana 

 or any other general feeder does. I should, however, mention that if 

 a half-grown larva be removed from its mine, and be so placed that it 

 can creep under a leaf or between two leaves, it first makes its retreat 

 secure with a little spinning, and then proceeds to burrow into the 

 leaf. This is a tedious process, taking three or four days, so that it is 

 quite possible by repeated interruptions to prevent the larva ever 

 accomplishing its purpose, and yet for it to remain healthy and pro- 

 duce the moth. Under these circumstances the ineff'ectual attempts 

 to enter end in a general excavation of the surface, much as if one 

 of the common Tortrices already mentioned had been at work ; but I 

 think no argument can be fairly drawn from this against the natural 

 habit of the species, which is to mine the leaf. 



