ARICIA MEDON. 269 



and bright red lateral flange line, all three fading out at the ends. 

 They differ little in size, but the contrast is rather great, the one in 

 4th (3rd ?) instar looks fat, distended, bare, and hairless ; it is 

 5.5mm. long, 2mm. broad, and 2 mm. high, highest at 1st abdominal 

 segment, dorsal surface of prothorax nearly vertical facing front, — 

 from lateral view, incisions deep, and segments rounded from mesothorax 

 to 6th abdominal, remainder tapering more rapidly ; end of larva is 

 nearly 05mm. beyond claspers. The end view shows a dorsal plain, 

 slopes flat, except for a slight rise half-way down ; the lateral flange 

 (at middle of larva) -f height of larva from base, below this the sides 

 slope in to prolegs. The lateral flange is so full and rounded as to have 

 an angle or groove above and below it. The hairs are faintly rufescent, 

 but on the distended larva, very inconspicuous from being thus scattered. 

 The other larva that has just moulted looks very hairy, so much so 

 that one would have to make allowances for the obscuring effect of the 

 covering to make out the exact form of the larva. The hairs appear 

 to be colourless, and in sunlight form a dense shining cloud along the 

 dorsal and lateral flanges, where they are longest if not most dense. 

 The length is about 6mm. The larva? eat by preference the young 

 leaves at the end of a growing shoot, and finish them so that there is 

 only rarely the appearance, so common earlier, of white spots of 

 cuticle, whence the parenchyma has been eaten away below. March 

 28th. — A larva, not full grown, but in last skin, when sulky and drawn 

 together, is 9*5mm long, 4-2mm. high, and 4 , 6mm wide. It is 

 thickest at 1st abdominal segment, diminishing rapidly forwards with 

 each segment, only slightly backwards to the 6th abdominal, where it 

 is nearly as wide, but only half as high, as the 1st; thence it dwindles 

 in a conical manner ; dorsally the first six abdominal segments (seen 

 laterally) are semicircles, the remainder, 7-10, slope regularly ; the 

 thoracic segments are flatter, the mesothorax has only a little of the 

 lapping over the prothorax, so strongly seen in Callophrys rubi. There 

 is a dorsal furrow, the dorsal flanges are about 1mm. apart, the 

 "slopes " are flat, i.e., as seen from back or front they present a straight 

 line. The lateral flange stands out angularly, and the line of tubercle 

 vi does so slightly, an effect much increased by, possibly entirely due 

 to, the strong line of hairs at that margin. The larva is a very 

 beautiful one, the rich rose-pink of the lateral flange contrasting with 

 the pale apple-green of the rest of the larva, all, that is,, 

 except the dorsal furrow which is purplish. These colour contrasts 

 are further much enhanced in effect by the haze of pale, darker than 

 silvery, less tinted than golden, hairs, which are especially massed 

 along the dorsal and lateral flanges and the line of vi, and less along 

 iii. The actual skin seems to be polished and reflects the light, 

 especially if bright, with remarkable effects, showing silvery lines down 

 the posterior border of the segments, a brilliant silvery line along the 

 lateral flange, sometimes with branches descending lower, and often 

 with a row of brilliant white dots on the eminences of the flange at vi. 

 All this is complicated by the difficulty of saying where the colours 

 really are, the actual skin, and layer immediately beneath, being clear 

 and crystalline. The lower surface has the green washed with 

 ochreous, but so as hardly to amount to olive. In bright sunshine 

 the hair-bases over the whole larva sparkle like minute gems. Another 

 specimen shows a white lateral line, not that this simple statement 



