The Beetles of the Moorlands 



in fact, whereas they are always red in the other species. 

 This phenomenon of a more or less light coloured 

 lowland insect being replaced at high altitudes and in 

 the far north and north-we A of these Islands by a form 

 very much darker in colour and often rather smaller, 

 but in every other respect identical is one aspect of 

 what is called Melanism, is not confined to beetles, 

 as there are many examples of it among the Lepido- 

 ptera (moths and butterflies), and no adequate explana- 

 tion of it has so far been discovered. In Coleoptcra 

 there are good examples in Notiophilus aquaticus and 

 Carabus arvensis, both of which are shining copper- 

 bronze in colour as they occur over the great extent 

 of the country, but often quite black in the mountains 

 of Wales and Cumberland and the moorlands of Scot- 

 land and Ireland. My own belief is that such melanic 

 forms are not the immediate result of altitude or 

 locality, but represent an older varietal race or form 

 which has died out or been superseded by a later 

 immigration in the south and east ; indeed even in the 

 localities where it exists at all melanism is not universal 

 under one of these stones for instance we may find 

 Notiophilus aquaticus quite of the normal colour. 



We have already taken N. biguttatus (see Plate II., 

 Fig. 3) and know the great bulging eyes and glossy 

 metallic elytra which characterize the genus. This 

 N. aquaticus (haunter of wet places) Fig. 5, Plate V., is 

 very like that species, the same colour and about the 

 same size, but it has no light patch at the apex of the 

 elytra, and the antennae and legs are entirely bronze- 



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