388 BRITISH BUTTERFLIES. 



first instar, and then nothing to approach say — the larvae of Ruralis 

 betulae.] Same instar (well-fed): The larva at rest is 3mm. long, 

 l'5mm. wide, an extremely short, round item, nearly as high as wide. 

 In one case the larva is green, with perhaps darker dorsal, and pale 

 lateral, line, and even, perhaps, some intermediate lines ; in another, 

 the dark dorsal line is faintly pink ; in a third, there is a strong 

 pink tone both dorsally and laterally. There is still quite a definite 

 " slope " from the dorsal to the' lateral ridges. Looking at the larva 

 end-wise, there is the double dorsal row of black hairs, with shorter ones 

 along with them, and some very short ones dorsal to them ; then there 

 are the lateral flange hairs, curved downwards in an upper and lower 

 row, and the " slope " is divided into three, about equal, portions, by 

 two rows of hairs, the upper curved upwards, and about half as long 

 as the long dorsal, the lower nearly as long and curved downwards ; 

 some shorter intermediate ones are not satisfactorily determined. The 

 hairs are more numerous and about 0'2mm. to 03mm. (a few 0-4mm.) 

 long. The prothorax has, over the dorsum, about thirty hairs on each 

 side, not specially arranged or grouped. The spiracle is right back in 

 the incision, looking as if in mesothorax ; it is accompanied by two 

 lenticles and a hair ; there is a group of smaller hairs down in 

 front, with, across the front, a number of pale circles, that may be 

 lenticles, the inner two seem to have colourless hairs. Doubtful as to 

 whether belonging to pro- or mesothorax are two median lenticles, 

 a fine hair, near the middle, on either side. On the meso- and 

 metathorax, on spiracular level, are two hairs, accompanied by a lenticle 

 that looks exactly like a spiracle, being on the same horizon ; each of 

 the abdominal spiracles is accompanied by two lenticles, looking very 

 like it ; on abdominal segments 6 and 7 there is an extra (making 

 three) lenticle and a hair ; these are all above and behind the spiracle ; 

 on abdominal segment 8, a hair and two lenticles ; a little above this, 

 and to the front of the segment, on the mesothorax and abdominal 

 segments, is a hair, another at the posterior border of the mesothorax. 

 Dorsally, taking two large central hairs to represent tubercle i, we have 

 ii just behind and outside it, a median small hair between, a hair 

 (small) in front of i, and another further out and further forward, close 

 to the front border of the segment, a longish hair lower (iii?), then the 

 front border one, and the one against spiracle ; the marginal group 

 numbers about eight ; the seta on i is about 04mm. in length, those 

 on ii and iii are nearly as long, and so are some of the marginals. 

 On the anal plate are eight or ten hairs and four lenticles. The hairs 

 are difficult to distinguish from a score or more round posterior margin. 

 The prolegs carry four hooks (in three sizes) on each pad. The skin- 

 surface is divided by a pavement-network, each cell of which carries a 

 minute central spicule. Third instar (laid up for moult) : 7*5mm. 

 long, 2mm. wide, 2mm. high, at the 2nd abdominal segment, which is 

 the highest point. The colour green, with red dorsal and lateral lines, 

 and variations as in last skin. The width is also greatest at the 2nd 

 abdominal segment; it narrows slightly to the 6th, more to the 8th, 

 whilst the 9th and 10th abdominals give a rounded end, just as the 

 prothorax does in front. There are no definite dorsal ridges, but, from 

 the narrow rounded top, two " slopes " fall to lateral flange ; they are 

 quite marked, but are a little full and rounded, not flat. Some of the 

 dorsal hairs are still a little longer than those on slopes, but, except 



