281 



BKITISH BUTTEKFLIES. 



in doing this she usually chose that situation where a small lateral 

 twig branched off, and fixed the egg usually just beneath this spot. 

 Volker took the butterfly home, as well as a sloe branch, in order to 

 watch more leisurely the further egg-laying ; in this he succeeded 

 perfectly. The butterfly and a branch of sloe (with as many twigs as 

 possible), placed in water, were put into a glass cylinder, 30cm. high 

 and 18cm. wide, closed with a piece of muslin, and the whole stood 

 on a window-sill in the sunshine. In this the butterfly lived till 

 October 15th, and laid exactly another two dozen eggs in the manner 

 above described ; some of these were, however, situated in the forks of 

 the twigs. The butterfly only laid when the sun shone ; on bright 

 sunny days she sought shelter under the shade of the leaves, a proof 

 that one ought to mitigate the sunshine and give the creature 

 something to drink. In spite of the fact that the incipient warmth 

 of the sun seemed to benefit the creature and induced her to spread 

 her wings if the rays were allowed to play on them for a time, the 

 fiercer heat in the still atmosphere of the glass cage compelled her 

 soon to close her wings. The peculiarities of her egg-laying still 

 continued ; the walking about of the butterfly and the seeking of a 

 suitable place for the egg, then the somewhat vibrating manner of 

 half opening the wings, the action in egg-laying, the closing of the 

 wings and renewed promenade. This female laid ten eggs on 

 October 7th ; the nearer, however, she approached her end, the 

 fewer became the number ; the last eggs were placed quite low down 

 on the branch ; no eggs were laid at all on the uppermost twigs. 

 Volker was not able to observe the butterfly taking any nourishment. 

 This female died with fully outspread wings in the sunshine ; it fell 

 off the leaves and remained lying on the upperside of the wings. 

 The egg of R. betulae hybernates just as the eggs of FJdwardsia w-album, 

 Strymon pruni, and Bithys quercus, and does not hatch till spring; it is 

 protected sufficiently by its adhesion, but apparently little by its 

 colour (being easily visible on the black bark of the sloe twigs). 

 The darkly-coloured eggs of E iv-album are exceptionally difficult 

 to discover on the similarly-coloured elm twigs." 



Ovum. — The egg is pure white in colour, and is of the ordinary bun- 

 shape, 0*77mm. across, 0'42mm. high, regularly domed. It has also 

 the usual Lycsenid hollows (hexagonal), with eminences at the angles 

 of the intervening walls, but these are elaborated in such a way as to 

 give a very special result, difficult to describe. First assume the egg 

 to be much smaller than stated, viz., 0'33mm. high, and then to be 

 overlaid by a coating, 0-09mm. thick on the top, of a pure w T hite, 

 glassy, or pith-like substance. Then make circular depressions in this, 

 - 06mm. apart (centre to centre), on the summit ; let these almost 

 reach the inner true shell and have hemispherical bases ; let them 

 widen a little at the top so as to cut one another almost half-way down 

 their depth, leaving pillars between, especially at their angles, standing 

 up to the original surface. More laterally, these circular holes will be 

 closer together and much smaller, being 0-01mm. in diameter, but 

 widening above in a crateriform manner and meeting each other so as 

 to have a sharp edge between and sharp points at the angles. The 

 result is that, on profile view, the tops show rather large, flat pro- 

 jections ; laterally and basally there is a forest of fine spicules, but 

 these can be traced as more or less in lines, as they follow the 



