MACRO-LEPIDOPTERA OF THE ISLAND OF ARKAN. 253 



Cidaria immanata. Cidaria popiilata. 



,, siiifumata. Eubolia bipimctaria. 



,, silaceata. Anaitis plagiata. 



Most of the Geometrae mentioned in this hst present but 

 little, if any, variation from the normal coloration of the species, 

 but a few call for some remarks. Boarmia repandata. — This 

 occurs sparingly, and the colour in no way approaches that of 

 the variety Sodorensmm. Ypsipetes elutata. — There appears to 

 be in Arran two races of this insect : one of the usual size and 

 colour of the southern varieties, and the other the small and dark 

 northern variety ; the former inhabits the low grounds and feeds 

 on the sallow, the latter is found higher up in the mountains 

 and apparently feeds on the heath. I have little doubt but that 

 the insects of Arran are very varied, its geological formation 

 consisting of such different strata as Devonian, Lias, Oolite, 

 Silurian, Granite, and other rocks. Larentia pectinitaria. — 

 Particularly large and richly coloured. Mclanippe fiuctuata. — 

 Very dark, and much suffused with black. Cidaria immanata. — 

 A most interestmg series of this species was taken, although 

 there is some range of variation, yet the prevailing colour of all 

 is greyish ; in fact at a little distance they could scarcely be 

 distinguished from the Cidaria russata taken in the Outer 

 Hebrides. It is remarkable that C. immanata has been taken in 

 Shetland and Arran ; in the former islands the insect — unlike 

 those of Arran — exhibits a prevailing reddish hue, but in neither 

 of these islands, so far as I know, does C. russata occur ; but in 

 the Hebrides it does not appear that C immanata has hitherto 

 been found, C. russata only. 



I have taken great care to verify the above singular case of 

 geographical distribution, and I trust that future investigation 

 will throw more light on the subject. 



These expeditions to the remote islands of Scotland are not 

 undertaken without great sacrifice of comfort, and are attended 

 with risk to the health ; and I regret that Mr. M'Arthur was 

 seriously ill during his visit to the Hebrides in the early jjart of 

 this year, or 1 have no doubt he would have added to our know- 

 ledge of the Lepidoptera of those islands. 



