144 THE entomologist's record. 



theory ? If he will show me a collection of insects made on any of oui* 

 large bogs, I will guarantee to show him any number of species proving 

 my point. He complains that I " argue from a special case, and assume 

 that the reply has a general application." I assume nothing of the kind. 

 I certainly argued that there was a large class of pale coloured species 

 belonging to very different groups of lepidoptera, which had a very 

 similar facies, such facies undoubtedly being entirely governed by 

 "natural selection." Mr. Eobson jumps to the conclusion that Macro- 

 (jaster arundinis, Lcelia ccenosa, Lithosia muscerda, Collix sparsata, the 

 genus Chilo, have very different habits from the Lencanklce, and yet, all 

 are " of ochreous tints, Avhich certainly is the prevailing hue in the species 

 that inhabit our swamps and morasses," I am quite certain that Mr. 

 Eobson is here floundering out of his dejith, that he knows nothing 

 whatever of the habits of 31. arundinis, L. ccenosa, L. muscerda, and the 

 genus Chilo, and that he has no concejDtion of the range of variation in 

 these species. I believe he has never seen one of these species in a state 

 of nature. I have seen them all but L. ccenosa, so I can safely leave the 

 entomological public to judge of the value of our respective opinions. 

 Granting that a certain percentage of the Fen (not bog) species are pale 

 in tint, what I wrote is still applicable to these as a grou}). Mr. Eobson 

 appears to fail to grasp what I have written. His failure to see the fact 

 that "■ natiiral selection " is in such districts, and under the conditions of 

 existence of these species, acting in direct opposition to the production 

 of melanic forms is unfortunate, but I see no immediate remedy. To say 

 that I "• have lost the thread of my argument," because I have got rather 

 out of the line he covild understand, is leather amusing. I import another 

 factor, viz. " smoke," says Mr. Eobson, in dealing with the modification 

 shown by marsh-frequenting species, near large towns. Certainly ! 

 I am sorry Mr. Eobson cannot compound the three probabilities here 

 referred to (moisture, smoke, and natural selection), but it would ap- 

 parentlj^ he waste of time to exjilain the matter further. 



Mr. Eobson unwittingl}^ proves in his reference to L. pollens, my 

 compounded notion with regard to this species. (1) L. 2)allens, when 

 it inhabits very wet places, should have a tendency to l)e dark ; (2) 

 L. pollens, in marshy places, rests on grasses and reeds, therefore " natu- 

 ral selection " causes it to respond to its environment, and makes it 

 pale ; (3) The reed-beds, sedges, grasses, &c., near large, smoky areas, 

 get dark, and "natural selection " at once steps in, and darkens the form 

 produced by 2, the natural tendency to vary being inherent b}' 1. Mr. 

 Eobson fails to compound these, and hence, I have " consciously, or un- 

 consciously, changed my opinion," and " have lost the thread of my 

 argument." Mr. Eobson, of course, finds it much easier to suppose this, 

 than that he is at fault and failed to imderstand my argument. 



The little care which Mr. Eobson evidently has bestowed on a sub- 

 ject which he treats with the utmost confidence, whilst other entomo- 

 logists have to view it from a distance, is evidenced when he, wishing 

 to prove his imaginary idea that I had changed my views, does it by 

 (pioting the following statement : — " But if moisture is to be taken as a 

 direct, rather than as an indirect cause, we should expect to find melanic 

 variation occurring in the swamps of Tropical Africa, in the Forests of 

 the Amazon, on the banks of the Mississippi, and in many other damp 

 climates, even within tropical regions, and I am not aware that this is 

 the case." This is a statement made by Lord Walsingham, in his Presi- 



