1896.] Ka^f:. —JIfe/anzsm in Camp to gramma biii7ieata. 77 



melanic tendency. I have specimens from Unst which are 

 similar to some of the Kerry coast forms, but are not so dark 

 as ab. mfiiscata. No remarkable aberrations occur inland at 

 Killarney or Kenmare, but on the shores of Dingle Bay, about 

 Dingle and Slea Head, a large proportion of very striking 

 banded and suffused forms are to be found. On the coast of 

 Donegal and at Killary Bay clouded forms occur also. It 

 would therefore appear that a tendency to dark suffusion shows 

 itself in the vicinity of the dark rocky shores of the south-west, 

 from Bantry Bay to Valentia on the mainland ; and when 

 isolated the phenomenon becomes accentuated to an extreme 

 degree, and a stable melanic variety arises and wholly super- 

 sedes the type. It is not difficult to imagine the stress of the 

 environment in an island such as I have described. The 

 herbage is sparse and the turf close- shaven by the wind, 

 affording little or no shelter for moths to hide in, and small in 

 comparison with the rock-surface. It is haunted by bats and 

 insectivorous birds such as Rock Pipits, Wheatears, and the 

 smaller gulls, which are most active in pursuit of insects, both 

 larvae and imagines. These no doubt thinned out the paler 

 immigrants from time to time as they were conspicuous on 

 the dark rocks, the darkest escaping in greater proportion, 

 and surviving to continue the progeny. Probably also similar 

 catastrophes to that of 1893, perhaps in less degree, occurred, 

 by which the stock was almost eliminated, so that a close in- 

 and-in breeding resulted in the selected race. The conclusion, 

 therefore, I have arrived at is, that on the rocky portions of 

 the mainland this species is acquiring a melanic tendency as 

 a protective adaptation, and chat isolation on a small area out 

 at sea, and a severe struggle to maintain their existence has 

 brought about the survival of the most melanic forms. On the 

 pale grey limestone tracts of the Co. Clare forming the shore 

 of Galway Bay, and in the Aran Islands I noticed that this 

 species had assumed a very washed-out and patternless form, 

 a protective adaptation in the opposite direction. Those who 

 lay much stress on moisture as a factor in the production of 

 melanism, over and above its influence in temporarily 

 darkening rock and tree surfaces, will doubtless be inclined to 

 point to the great rainfall for w^hich Kerry is notorious. And 

 indeed :io more crucial test could be produced than the results 



