170 TFTE entomologist's RECORD. 



will on occasions), for that tree grows naturally in a sandy or peaty soil, 

 while the elm,^ which is the tree most affected by the larva, has no such 

 predilection, but rather the contrary. It is plain and palpable then 

 to any one who prefers facts to fancies, that so far from the wonderful 

 resemblance of this moth to a stem of the silver-birch being a protec- 

 tion to it, it would have the exactly contrary effect when in view of all 

 the birds in the neighbourhood on the green leaves ^ of the elm, or 

 any other tree in Nature." 



It will be readily seen that the reverend gentleman is quite sensible 

 of the remarkable resemblance which the two species cited bear to their 

 respective foodplants or probable surroundings, and my own conclusion 

 is that he will not, rather than can not, see that this resemblance is 

 protective, and so invents arguments of a frivolous nature to disprove 

 the theory ; and even when speaking of Leptograniina literana he com- 

 mits himself so far as to say : — " But if the eye of an entomologist can 

 detect the little insect, even with this protective disguise, how much 

 more readily must that of some small bird or other creatures in search 

 of its food, with the hundreds of lenses of the eyes that some of them 

 have, given them by Nature to aid them thus to get their livelihood ? " 

 so that he admits it to be a protective disguise, and then contradicts 

 himself without apology. Now when an entomologist is searching for L. 

 literatia or any other moth, generally speaking, his eye is sensible of 

 no other object, being trained by experience to note the shape of a 

 moth ; whereas a bird on the look-out for a dinner is more likely to 

 pass over the moth, which to all appearance is part of the lichen on 

 which it rests, for the little black beetles and other more conspicuous 

 insects with which the lichen teems. The lichen-feeding species afford 

 several good instances of protective resemblance ; most fresh in my 

 mind now is Cleora lichenaria. No one who has hunted for the larvae 

 of this species could help being struck by the resemblance it bears to 

 lichen, and the meagre result of searching for an hour or so bears 

 ample testimony that the resemblance is protective. The same remark 

 might apply to the imago ; indeed, we hear of this variable insect 

 adapting its colour by " natural selection " to the colour of the lichen 

 on which it rests ; for instance, in districts where yellow lichen prevails 

 there is a preponderance of the yellow variety of the moth ; in the 

 only locality for the species in this district of which I know, the yellow 

 form is a rarity, greenish-grey being the prevailing colour, as it also is 

 of the lichen. Bryophila muralis and perla^ two species feeding on 

 lichen growing in old walls, are in the perfect state protected not only 

 by their resemblance to the liclien, but also to the walls on which they 

 generally rest, glandifera (^muralis) being especially hard to see. Mr. Tutt 

 states {British Noctuce and their Fars., vol. i., p. 8) that at Deal, where 

 B.perla occurs commonly, he gets the yellow forms on a wall covered 

 with yellow lichen, and he further informs me that he hardly ever gets 

 a yellow one on any other wall in the town. I have taken several 

 yellow perla here, but cannot say for certain on which walls. One thing, 

 however, I did notice last year, that on a certain white wall I got a 

 larger percentage of very light specimens. Although there are endless 



^ Surely willow and sallow are the trees most generally affected in Britain. I find 

 a large number are again feeding in my garden this year both on birch and oak. — Ed. 

 - Is not this assumed habit imaginary ? — P'D. 



