190 BRITISH BUTTERFLIES. 



structure covering the top of the egg. This is, though so different, 

 essentially the same as the rest of the coating. It is a network of 

 very fine, hardly visible, lines, the cells are again about 0-04mm. in 

 diameter, but are quadrangular, nearly square, where, half-way up, they 

 are best developed and seen, the bounding lines being lines crossing each 

 other and winding spirally out from the centre (engine-turning). At 

 each angle of the crossing of the lines rises a slender hair-like spine, 

 about 0-04mm. long, and apparently faintly knobbed. These fail in 

 the centre, where, in the middle of the rather flat top, is a depression 

 about O09mm. in diameter. On putting an egg in water on a slide, 

 and viewing it by transmitted light, the central solid egg is seen very 

 dark and contrasting with the light coming through the marginal 

 coating (containing air). Eefraction makes measurement untrust- 

 worthy, but the actual diameter of the real egg (as apart from coating) 

 seems even smaller than stated above, about 0'73mm. or 0'75mm. 

 In the dark part of the egg is seen a transparent slip, which is easily 

 seen to be a vacancy, extending along one margin of the contained 

 larva, due to its curled-up position ; and across this two or three 

 larval (dorsal ?) hairs lie at an acute angle. If any doubt existed 

 about this it is removed by warming the egg by breathing on it, when 

 the larva makes several obvious movements. [To make assurance 

 doubly sure an egg is opened and the larva extracted.] It is possibly 

 in connection with the mature embryo being inside that the upper 

 dark central portion of the egg presents a different tint on the upper 

 flat portion, instead of the dark chocolate tint of the circumferential 

 portion; this has a slaty-grey tone, suggesting, as may be the case, 

 that a layer of air here intervened between the eggshell and the larva, 

 the extracted larva being of a deep, almost black, brown, and the egg- 

 shell colourless when the larva is removed. The uppersurface of the 

 egg then presents four zones of different colours and different slopes. 

 Centrally, the micropylar circle, 0'09mm. in diameter, hollow. The 

 leaden zone, about 0-4mm. in diameter, nearly flat, but curving into 

 the chocolate side slopes, 078mm. in diameter, and the frill of white 

 spines or tufts, about 0'08mm. across, this is really white, but sufficient, 

 if the dark colour of the larva (or background, back or other ?) is 

 refracted through ifc, to give it a yellowish tinge. The micropylar area 

 magnified shows an area of 0-15mm. in diameter, in which the 

 reticulations of the eggshell proper are visible; outside this, whether 

 they exist or not cannot be seen, owing to the additional surface 

 coat. Centrally is a rosette of five cells meeting at a central point, 

 each 0-03mm. in length, surrounded by others of about the same size, 

 but not being drawn out to a point are variously polygonal, and about 

 0-025mm. in diameter, one or two look as if trying to press in to form 

 members of the central rosette. They are visible, two or almost three 

 deep, outwards from the five central cells (Chapman, March 26th, 1907). 

 Silk-spinning of larva in preparation for pupation (antea, p. 169). — 

 Vers la fin de Juin, 1780, plusieurs de ces chenilles s'attacherent chez 

 moi, soit contre des feuilles, soit contre les parois des bouteilles ou. je les 

 avois renfermees, avec le lien de fils de soye que j'avois tant envie de leur 

 voir travailler, et ce fut devant moi que plusieurs s'attacherent. Pour 

 entendre comment elles en viennent a bout, on se rappellera que les 

 chenilles peuvent allonger et raccourcir leur corps, qu'elles peuvent 

 gonfler certaines parties aux depens des autres, c'est de la que depend 



