142 THE entomologist's recokd. 



man who got near a comprehension of the subject at that time. To say 

 that Mr. Birchall's paper " comprises almost everything that has since 

 been written on the subject," is an opinion ridiculous in itself, and can 

 only be meant to throw dust in the eyes of those entomologists who are 

 not scientific, and is disi^roved by Mr. Robson's own paper, since he 

 finds something else to write about. Such a statement of such a paper 

 is not likely nowadays to pass muster with men who read and think 

 for themselves, and who begin now where the entomologists of twenty 

 or thirty years ago left off. Even Mr. Robson says of Mr. Birchall's 

 paper, in his next paragraph, that " many points briefly touched on by 

 Mr. Birchall were afterwards discussed at length." 



Mr. Robson refers in a very strange manner to certain remarks made 

 by Mr. Dobree (D'Obree of Mr. R.'s paper), in which he showed that the 

 NocTU^ of high latitudes were not necessarily melanic. He says that 

 Mr. Dobree " is a student of Noctu^ only, and that no conclusion based 

 on the study of an entire Order could be upset by one portion of such 

 Order." But where, I would ask Mr. Robson, can melanism be so well 

 studied as among the Noctu^ ? For every example of melanism in the 

 other gi-oups of Lepidoptera, Nocture give a dozen. In fact, it is only 

 among this family that sufficient material can be gathered for generali- 

 sation, the examjiles among the Geometr.e being much more limited (as 

 might be expected from their general habits and the action of " natural 

 selection "), and, with very few exceptions, limited to those species 

 whose habit it is to rest on tree trunks, fences and similar places. 



Mr. Robson's reference to Lord Walsingham's paper, which has 

 been discussed at length jireviously, is unfair to its author, since Lord 

 Walsingham had ah-eady withdrawn his statement " that melanic forms 

 were characteristic of high latitudes," and has substituted " suffused 

 forms " (Trans. Ent. Soc. Lond., 1890, pp. liv.-lv.), and it appears to be 

 begging the question, so far as Mr. Robson is concerned, to repeat the 

 statement. Lord Walsingham's j^aper simply shows that dark coloration 

 may be an advantage to the insects possessing it in high latitudes and 

 altitudes, but it does not attemj^t to show the cause of melanism, which 

 is what we have to deal with. 



With regard to the other notes referred to by Mr. Robson, that 

 referred to by Mr. Cockerell supports my view, but that of Mr. Dale 

 (Brit. Nat., p. 65), is really not deserving criticism. Really, it is 

 difficult to get down to the level of a man who denies the primary laws 

 of physics. 



Now, with regard to Mr. Robson's remarks on my own jDamphlet, I 

 must begin by thanking that gentleman for his kind intimation to the 

 entomological public that the pamphlet has attracted a good deal of 

 attention, although his way of announcing the fact certainly leaves 

 something to be desired. His reference to the early part of my papers 

 as " a clearly-defined and intelligible theory," leads me to suggest that 

 so long as I was only exjilaining the very elementary facts connected 

 with melanism, Mr. Robson was able to follow them, but when I went 

 off into the secondary and more indirect causes bearing on the subject, 

 which required a more complete grasp of general scientific principles, 

 my theory becomes " dim and obscure," and " so many side issues are 

 raised and discussed that the original idea is almost, if not entirely, lost 

 sight of." That is, I presume, Mr. Robson M^anted something very 

 straightforward to be presented to him, something that would be easier 



