14G THE entomologist's kecokd 



attributed to the long succession (vinprececTentecl) of wet seasons we 

 have passed through," and yet goes on to conclude (from this, I pre- 

 sume) that " Dr. Chapman, who is one of the most thoughtful and 

 original of all students of Lepidoptera, does not support the idea that 

 moisture produces melanism." Truly, these depths are beyond me. 

 The quotation Mr. Eobson gives appears to be a sufficient refutation of 

 his own conclusion. Mr. Rol:)son clearly does not discriminate between 

 the two effects of moisture, the effect " that selects varieties " and 

 the effect " that makes them." So far as we have been able to get at 

 the latter. Dr. Chapman's notes (Melanism and Melanochroism in British 

 Lepidoptera, pp. 60-64) are lucid enough. Mr. Eobson seems to have' 

 overlooked them, or not to have noticed that they deal with the 

 matter. 



Some of the odds and ends of Mr. Robson's paper are most startling. 

 Mr. Rol)son's want of knowledge of the rainfall of our Fen districts, of 

 the response to environment of our Fen species, of the influence of the 

 Gulf Stream on the meteorology of the British Isles generallj^ and of 

 certain parts in particular, leads one to suggest that there are still a few 

 books on meteorology and phj'sical geogi-ai)hy to be obtained in some of 

 the various libraries scattered over the country. He also states, too, 

 that " these melanic forms did not exist half a century ago." Wliat 

 melanic forms ? I would ask. The melanic forms of Gnophos obscurata 

 on the peat bogs of the New Forest or on the dark rocks of Perth ; the 

 Ijlack Xylophasia polyodon of the Irish coast, Scotland, etc. ; the black 

 Agrotis Incernea of the Kincardineshire and the Irish coasts ; the dark 

 barrettii form of Diantho'cia Infeago or the manani form of D. ccesia ; the 

 dai'k Scotch forms of Larentia ccesiata, or the black moorland forms of 

 Hy2>sipetes ehitata ; the Scotch plmnhaia form of Melanthia rubiginafn, 

 the dark Wicken form of Acidalia bisetata, or the Dartmoor form of 

 A. marginepunctata ; the Wicken black var. of Chilo pliragmitellus, and 

 endless othei's ? If he say so, I am certain lie stands alone, and the 

 statement would be laughed at by every scientific lepidopterist in the 

 country', and I would suggest a re-reading of Melanism and Melanochroism, 

 &c., i^p. 42-43, and reference to elementary text-books on the areas in 

 Britain Avhich used to be covered with forest lands. On the other 

 hand, if he refers to Amphidasys betidaria var. doubledayaria, to Folia 

 chi var. suffusa, to Ciispidia psi var. svffnsa, or Eupilhecia rectangulata 

 var. nigrosericeata, I should be inclined to agree with him, as the 

 present conditions of environment were so different then from what they 

 now are ; but ages before that, when the physical geogi-aphy of England 

 was somewhat different from now, when large forests were the rule,, 

 dark forms probably existed, and the species have simply reverted by a 

 series of changed conditions in their environment in recent years. 



But what new facts does Mr. Eobson give us relating to melanism ? 

 Not one that has not been noticed before. What new theory does Mr. 

 Eobson bring forward to replace the ideas he vainlj^ tries to overtlu*ow ? 

 None I Not one single original idea of any description. He certainly 

 offers a warmed-up, second-hand edition of Lord Walsingham's theory, 

 from which the latter has more than half withdrawn. " Absenxje of 

 sunlight ! " This, then, accounts for the effusive praise given to Mr. 

 Birchall's elementary paper of so many years ago. That gentleman 

 casuaUy mentioned that " the clouds in Ireland " and " the smoke in 

 Lancashire " intercepted some of the sunlight, and this accounts for 



