204 A NATURALIST IN HIMALAYA 



pressed closely against the rock, and so carefully con- 

 cealed that it can be detected only by the sharpest eye. 

 It is an excellent example of a protectively coloured 

 species that blends with a grey weathered stone. 



In marked contradistinction to the Gnophus is 

 another nocturnal moth, Boarmia adniissaria, a smaller 

 species about two inches in expanse, with brown wings 

 streaked at intervals with bands of black. This moth 

 would gain no protection on the light-coloured lime- 

 stone, so it resorts to the trunks of the trees. It 

 spends the day attached to the bark of the pine, 

 cherry, sycamore, silver fir and other forest trees. Its 

 pattern of coloration bears the very closest resem- 

 blance to the bark on which it rests, and makes it 

 a difficult insect to discover until it flies out into 

 the air. 



These two moths, the Gnophus and the Boarmia^ 

 cannot but arouse interest in the principles of pro- 

 tective coloration, so perfectly adapted is each to the 

 nature of its haunts, the one to the cliffs, the other to 

 the trees, and each keeps so exclusively to its own 

 respective habitat. 



Another little point of interest was that the different 

 species of Boarmia did not necessarily seek protection 

 in the same haunts. For instance, Boarmia granitaria 

 was a smaller and greyish-coloured species, and it used 

 to rest by day not upon the trees but on the slabs of 

 limestone, with which it harmonized very well. Like 

 the other species, it flies by night and often comes 

 about a lamp. The colouring of its under surface is 

 a little conspicuous, but this is of no disadvantage since 

 it rests with wings outstretched and pressed firmly 

 against the stone. 



