ARICIA MEDON. 261 



upperside of the leaf, upon which the egg was laid, to the underside, 

 and feed there (Harrison). The last statement should be specially 

 noted with regard to vars. salmacis and artaxerxes, all other writers, 

 whose observations have been made on the less northern forms, speak 

 of the eggs as laid on the underside of the leaf. 



Egg. — Smaller than the egg of P. aegon, though very like it in 

 form and sculpture. Circular, flattened, with a central depression on 

 the upper surface, the shell covered with a coarse, prominent 

 reticulation, gradually becoming finer towards the nearly smooth 

 depression ; its colour, a pale greenish-drab, continues to the last 

 (Buckler). — The egg, when first laid, is of a beautiful pale green colour 

 — resembling the shade of green in the imago of Geometra vernaria — ■ 

 but two days before hatching it changes to a uniform dull whitish hue 

 (Ray ward). — The egg (laid August 22nd) had the ordinary form of 

 those of the genus Lycaena, w r as greenish-white, and retained this 

 colour till August 31st, when it was white, and had above a large 

 kidney-shaped hole, through which the larva had escaped (Zeller). — 

 The egg is white, owing to the outer coat, but beneath this a green 

 colouration (of egg contents) is very distinct (Chapman). 



The egg is of the usual Lycamid shape, i.e., flat top and bottom 

 with rounded edges, like a cheese. It differs from the strictest pattern, 

 by the bottom being distinctly wider than the top, by the top being- 

 very faintly convex, and its margins more rounded than are those of 

 the base. The extreme width to the ends of the knobs or pillars is 

 O50mm., the egg itself is smaller, smaller even than 0*45mm., which 

 is the width to the bottom of the deepest hollow between the pillars 

 that can be seen on the margins when the egg is viewed from above. 

 The bottom (including adventitious coat), is about 042mm., the top 

 about 038mm., the height (to top of pillars) is about 0-24mm. at edge, 

 0-26mm. at middle of top. The pillars at angles of network stand up 

 above the hollows from , 02mm. to perhaps as much as 0'03mm., 

 where highest round the margin, towards the base they look broad, 

 and compounded of several fused together ; this may be an optical 

 mistake, most have a slight summit expansion. The meshes of this net- 

 work, towards and on the base of the egg, are hexagonal, but on the upper 

 parts of the sides are usually quadrangular, with the sides oblique, formed 

 by lines obliquely cutting each other, and about 0-04 5mm. on either side. 

 (Described August 14th, 1907, from an egg laid at Cauterets, Pyrenees). 

 The egg is of the usual Plebeiid form, but not quite so flat on the top 

 as usual, even taking the tops of the white pillars it is still a little 

 convex ; still it is a flat top, in the sense that the sides do not run up 

 into it as a regular dome, but curve rapidly into it, the upright side 

 being less curved than at the margin and the top itself only slightly so. 

 It has the usual w T hite colour, green where the contents can be seen 

 between the white ribs. It is 0'5mm. across, actually — not a round 

 number at a guess, or 0'45mm., as nearly as one can see, is the 

 diameter of the actual egg, apart from the white coating. The 

 columns are tall, the cells for the most part square, with sides about 

 O035rnm. The ribs do not hang as it were in catenary curves from 

 the summits of the columns, but from near their bases, and so the 

 walls beneath them are comparatively short. The columns are in fact 

 columns, standing out thick and high above the rest of the sculpturing. 

 The slightly domed (not quite flat) top perhaps shows Theclid 

 affinities (Chapman). 



