126 BEITISH BUTTEKFLIES. 



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

 and that he carefully watched the same movement made both by this 

 species and Thestor ballus. He adds: "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 abundant 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. ballus at Ste. Maxime 

 anything to do with the different habit of C. rubi? When on the 

 ground, T. ballus secures no cryptic advantage, but both species 

 certainly do when on vegetation, though there is also a maximum 

 exposure to the sun as well as a maximum of display. Neither insect 

 ever shows the upper surface when resting, not even the coloured 

 T. ballus 2 • The paradox, that this attitude secures both the 

 maximum of display and a large amount of cryptic effect, I find 

 difficult to deal with, nor can I form any opinion as to whether the 

 butterfly is more or less conspicuous owing to the special orientation, 

 but certainly one side of the insect secures a vertical exposure to the 

 sun's rays." Prout observes (op. cit., p. 214) that, on June 5th, 1906, 

 at Westwell, in Kent, he chanced to get a specimen of C. rubi, which 

 he had netted, to " settle " on his forefinger, and to remain there a 

 minute or two. He adds: "Noticing the 'twist and twinkle' resulting 

 in vertical exposure of the undersurface to the sun, it occurred to me 

 to move my finger gently in such a way as to reverse the conditions, 

 i.e., to expose the butterfly horizontally to the sun. Immediately, though 

 without undue haste, it turned round to regain the position it had chosen. 

 I repeated the experiment six or eight times before it finally flew away, 

 and each time with the same result. This convinces one that the attitude 

 is one of real importance, and to incline to the view that it is cryptic in 

 effect, and it is, at least, interesting that C. rubi, resting among 

 leaves where it has little to fear from its own shadow, settles in a 

 position quite antithetical to that assumed by certain ground-resting 

 Satyrids, and others, which reduce their shadows to insignificant 

 dimensions." Of the movements of the hindwings when at rest, 

 Swinton notes (Ent. Mo. Mag., xiv., p. 210) that he observed, on two 

 occasions, an example sitting on a bramble leaf, with shut wings, 

 when it lifted its underwings alternately, and, in a leisurely fashion, 

 rubbed them backwards and forwards over the forewings. He suggests 

 that the movement may be a stridulatory one, and observes that, in 

 C. rubi, the scales on the overlap of the forewing are supplanted by a 

 patch of hair, whilst, just above, the anal vein is bare and raised. 

 This bare raised portion is crossed at uniform distances by pronounced 

 striae, which indicate internal diaphragms, and constrict the tube into 

 a series of bead-like formations, whose surface, in common with that 

 of the other forewing veins, is pitted, or bears a row of obsolete tubercles 

 resembling those constituting a musical organ in certain Acridiidae 



