BUTTERFLIES AT REST. 169 



ticularly attracted my attention are rather what might be called the 

 attitudes when settled, rather than when at rest, i.e., the attitudes 

 assumed for a few seconds, or minutes, during the period of daily 

 activity. That these two series of attitudes are closely related to, and 

 have considerable value in explaining, each other, is no doubt the 

 case. Indeed, the temporary attitude no doubt leads up to, and pos- 

 sibly originates, the true resting attitude. This follows from the 

 circumstance that when the butterfly is temporarily resting a sudden 

 failure of sunshine may necessitate its accepting as, or at any rate 

 changing at once into, the permanent attitude that which it then has. 

 There is nevertheless a certain antithesis between the two attitudes. 

 Dr. Longstaff shows that the prolonged resting attitude has reference 

 principally to effective hiding. I have always regarded the temporary 

 attitude as pointing, on the contrary, to effective display, and especi- 

 ally to securing a maximum solar radiation. 



The Vanessas illustrate most pointedly the difference of the two 

 attitudes and the obvious connection between them. All the species I 

 know are fond of settling on a road, a stone, a wall, or other bare 

 place; immediately they turn their tails to the sun, and, after a slight 

 flap or tw^o, lay the wings flat on the ground, indeed more than flat, 

 as the head is somewhat raised, and the borders of the wings touch 

 the ground all round — the position that is given to an insect in the 

 good old-fashioned English setting (indeed this setting is probably 

 in reality an attempt to reproduce this butterfly attitude). The 

 insect in this way receives a maximum of sunshine, whether because 

 he finds it grateful and comforting I do not know, but it certainly, by 

 securing a maximum amount of light, gives the colours the greatest 

 brilliance they admit of, and it would be difficult to surpass the 

 display made by a Pyrameis atalanta, Vanessa io, or Euvanessa antiopa 

 so resting. How closely this is related to the prolonged resting atti- 

 tude is obvious, since it is at once assumed, if the wings be thrown 

 back, as occurs during any temporary passing of a cloud over the sun. 



I have taken a recent opportunity of seeing a few butterflies at 

 Hyeres, to refresh my recollection on some of these points. Callophrys 

 rubi when it settles instantly makes a curious little twist and twinkle. 

 I had never tried to understand what this meant, but I have recently 

 had the opportunity of carefully watching the same movement made 

 by Thestor ballus, as well as observing C. rubi itself. The movement, 

 which is almost part of the process of settling, places the insect at 

 once, with one side (without preference for either) towards the sun, 

 the wings closed, and the sun vertical to the exposed undersurface ; 

 T. ballus will settle on the ground, but by preference on some portion 

 of a plant, and C. rubi invariably on the leaves of some tree or shrub. 

 Such, at least, was the case at Hyeres, where the butterfly was abund- 

 ant in some places. At Ste. Maxime, however, a little later, where it 

 was equally common, it was rather fond of settling on stones and 

 pathways. I feel confident that this difference of habit in the species 

 at the two localities was real, and not due to any serious defect of 

 observation, though it is possible that occasionally a C. rubi on the 

 ground may have been mistaken for T. ballus. Had the absence of 

 T. balhis at Ste. Maxime anything to do with the different habit of C. 

 rubi ! 



When on the ground T. ballus secures no cryptic advantage, but 



