116 BRITISH BUTTERFLIES. 



each head. Still many eggs may be found on one flower-head, but 

 almost certainly each laid by a different imago (Chapman). Two ova 

 found on the calyces of a head of Anthyllis vulneraria on June 20th, 

 1900, at Reigate (Prideaux). 



Ovum. — The egg presents an almost circular outline about -4nmi. in 

 diameter, very flattened, the thickness being rather less than half the 

 diameter. It is pale green in colour, with the surface crossed, as in 

 the egg of Ayriades bellart/us, by two series of oblique white lines, 

 cutting each other in opposite directions, and dividing the surface of 

 the sides into rhomboidal, and higher up into irregular polygonal, 

 divisions. The upper surface is not depressed, although somewhat 

 flattened, and, in this respect, differs greatly from the egg of A. bellar(/iis. 

 The surface of the upper part of the egg is almost exactly like that 

 of the sides, whilst, quite at the apex, a comparatively large and dis- 

 tinctly green micropylar area is conspicuous. At the exact centre of 

 this area is a white point. At each of the points of intersection of the 

 surface reticulation is a distinctly raised white knob ; these are, how- 

 ever, less marked than those of A. bellanjus. As the egg matures it 

 loses its bright green colour, and becomes somewhat yellowish. 

 [Described June 24th, 1898, from eggs found by Mr. R. D. Postans 

 at Eastbourne, June 22nd, 1898.] (Tutt). Egg green, with white 

 coating. By reflected light it looks nearly white, but when any light 

 passes through the egg, the green colour is correspondingly distinct. 

 The white adventitious coating is thin on flat upper surface, and 

 apparently wanting centrally. The width is 0'45mm., the height 

 0*22mm. It is cheese-shaped, that is the top and bottom flat, the 

 margins rounded. The flat top is about 0'38mm. across, the rounded 

 margin therefore extends beyond this about 0-03mm. on either side 

 (or rather all round). The top and bottom seem to be not absolutely 

 flat, but rise a little. The centre of the top, for about 0-10mm. across, 

 is green and duller than the rest of the top which is overlaid with 

 whitish, corresponding with the density or absence of the whitecoating, 

 which is slight till quite the margin of the top. The whole top is reticu- 

 lated in irregular cells, the centre being, apparently, the ribbing of the 

 egg-shell itself, the outer part having a white coating added. The cells are 

 about 0-025mm. in diameter, about half this round the micropylar area. 

 Towards the margins, where the white coating gets thicker, and all 

 round the sides, the intersections have short raised pillars, with three- 

 or four-fold knobs at top. The cells on top are somewhat irregular in 

 form and arrangement, and may be so more or less down the sides, but 

 here and there a whole side has the ribs running obliquely down, 

 crossing one another (engine-turning pattern) making the cells fairly 

 square, or at least rectangular. In the central circle (O'lmni. across) 

 where the cells are all smaller, there is a central spot (hardly a cell) 

 about 0'002mm. across. Round this, six cells of various sizes, all 

 rather pear-shaped, with narrow end to centre, form a micropylar 

 rosette, but they are less regular than one usually understands by that 

 phrase. Round these, two rows of the smaller cells fill up the central 

 area. These central cells carry several dots each as a sculpturing, as, 

 indeed, do the other cells, when the white coating permits their being- 

 examined (Chapman, June 21st, 1908). Very small, shaped like the eggs 

 of its congeners, i.e., round, but more flattened than globular, with a central 

 depression on the upper surface ; this depression is the only place in 



