42 



with the rocks upon which the insect habitually rests in that island. 

 Mr. Jenner Weir has named this form sodorensium (Entom. xiv. 220). 



I should say that the representatives of B. repandata in the Isle 

 of Lewis are but little affected by crossing with forms from the 

 mainland of Scotland, in fact the small size of the specimens is very 

 suggestive of an impoveriched strain, probably the result of isolation 

 and consequent inter-breeding. 



In some parts of North Devonshire B . repandata varies from a 

 pale grey with few markings, through grey with ochreous tinge and 

 distinct lines, to an almost uniform smoky grey brown, together 

 with a predominant banded form {conversaria). This foim also 

 varies in depth and tone of colour. The species is common all 

 along the coast district between Ilfracombe and Lynton, but it is 

 found to be most variable in the charming little oak woods in the 

 glens by the sea, and in those places the var. conversaria is more 

 numerous than the type, if it be possible to speak of a type where 

 all that are not of the banded form are of such various patterns 

 and shades of colour. 



Conversaria and the more or less typical forms rest on oak trees, 

 and in this position the banded form is quite secure, its coloration 

 harmonises with the lichen-clad oaks so well, that the insect's de- 

 tection is a matter of difficulty. My first experience with the banded 

 variety led me to suppose that this form would be easily seen when 

 at rest ; but what I observed of its habits afterwards convinced 

 me that the first specimens of conversaria I had seen were for 

 some reason unfortunate in their resting-place. Occasionally re- 

 pandata was observed sitting on old walls, also on rocks, of which 

 latter masses of various sizes occur in all the woods. Many of the 

 repandata captured or bred would have harmonised well in colora- 

 tion with the rocks, but only few specimens were actually seen 

 thereon. 



The present sylvan character of those North Devonshire localities, 

 to which reference has been made, is a feature of comparatively 

 recent date, and is due to man's agency. Without doubt the low 

 growing herbage, such as bilberry and heather flourished there, 

 though perhaps not so luxuriantly, ages ago. Possibly birch and 

 sallow of a scrubby growth may also have existed before the oak 

 trees were planted. Then, as now, the larvae of Boarmia ?-epa?idata 

 would feed on the bilberry and heather, and the perfect insects 

 would probably rest on the rocks. After the oak trees were planted, 

 and as they increased in size, the herbage, including bilberry and 



