56 



THE BRITISH NATURALIST. 



PMarch 



" carpets " to illustrate his paper. Mr. Milton, Heliophobus hispidiis, Nodua glareosa, 

 Coleoptera : — Mr. Elliman, Mycetophagus atomarius, Litargus bijusciatue, Cicone. 

 variegatus, Dromius quadrinotatus, Sitnhis angustatus, Rhizophagiis bipustidatus, and other 

 beetles. Mr. Milton exhibited Nacerdes melamira, Alphitobius piceus, Carabus nitens, 

 Calosoma inquisitor, and Panagaus crux-major. 



The Geometrid Genera Melanthia, Melanippe and their Allies, — -Mr. Tutt said that he had 

 chosen the geometrid genera of " carpet " moths because they exhibited, perhaps better 

 than any other group, changes which were now in progress. It was generally accepted 

 by scientific men that transverse bands on the wings of lepidoptera had been formed by 

 the union of transverse lines, and that many species exhibited incomplete bands, the 

 incomplete part being formed of wavy lines. Attention was drawn to the fact that 

 the moths of these genera rested with outspread wings on the rocks, tree-trunks^ 

 . palings, ete. ; and that, taking into consideration the probability of a miore humid 

 climate in the British Isles when they were miore covered with wood, there was the 

 consequent certainty of a natural darkening in colour of species with such habits ; 

 it may be safely assumed that the darker specimens with transverse lines represent an 

 older form, and that, therefore, the Larentia was propably one of the oldest genera 

 in this group. As types of the changes that may have occurred, Melanthia rubiginata, 

 Melanippe monianata, M . Jluctnaia, snd Camptogramma bilineata were dealt with at length 

 All these had, in one or other of the humid districts to the north or west of the 

 British Isles, a form with dark ground colour crossed by transverse lines, the ground 

 colour becoming whiter and the transverse lines coalescing into banded form as 

 more open, drier, southern or eastern localities are reached. In the north and west of 

 Scotland, and in some parts of Ireland, tKe prevailing form of M. flnctvata is dark 

 grey in colour, with transverse lines, the central area often being without the slightest 

 tendency for the transverse lines to assume a banded form ; but as we come south 

 ^he ground colour becomes paler in some localities, and, at the same time the central 

 band necessarily becomes more marked until in the seuth of England and on many 

 parts of the Continent, the ground colour has become white, and the central band 

 partly disappears, often forming only a small dark blotch on the costa, or being 

 entirely absent. .Occasionly dark specim.ens and completely banded forms are 

 captured, but these must be looked upon as simply reversions to the darker form. 

 M. Dwntauata, taking the Hebridean and Shetlandic forms as nearest to the type' 

 shows a similar development, but the manner of suppression of the central area of 

 the band shows m.ost clearly in a long series from various localities. The special 

 development relative to M. JiiU^^in at a was also entered into; a comparison of the 

 Lancashire and south coast forms of M. galiata was made, and the darker ground 

 colour and central band of the former noted. C. bilineata has a dark ground colour 

 and is crossed by dark transverse lines in the majority of Shetland specimens ; Scotch 

 specimens also tended to be dark in many localities ; as we got father east and south 

 there was a greater tendency for both sexes to become golden, yet in many southern 

 localities, and in some years more than others, a large percentage showed reversion, 

 by developing a dark central band, more or less complete. These dark specimens in 

 the south were nearly always females, and hence this threw a side-light on sexual 

 dimorphism in this group. Mr. Tutt suggested that it was quite open to 



