220 BRITISH BUTTERFLIES. 



but the abundant hairs that give a yellowish tone to the larva, are 

 marvellous when somewhat magnified ; their bases are like a cog- 

 wheel, laid flat on the skin, with a very short clubbed hair rising from 

 the middle, and both, sparkling like crystals, seeming to be of quite 

 transparent glassy texture. The flight of lenticles accompanying the 

 spiracles is black. The hairs vary in different regions, and will no 

 doubt be very interesting when seen in a mounted skin. Fourth instar 

 (nearly full-grown, April 27th, 1908): When stretched, about 12mm. 

 long, 2'8mm. wide, and nearly 3mm. high, rather less when stretched 

 and active ; when walking, the larva narrows from the 6th abdominal 

 segment (3mm.) the broadest (segment), to themesothorax, where it is 

 2*2mm. or 2-3mm. wide. Seen on end, the lateral flange is well above the 

 surface of rest ; the slopes are faintly rounded, or say flat, but slightly 

 full, the deep brown dorsal plain, about 0-3mm. wide at mid-dorsum, is 

 flat, and separated by a ridge (flange) from the slopes on either side ; 

 this ridge is, however, slight, but made very pronounced (on end 

 view) by the crest of rufous hairs. From the mesothorax to tbe 6th 

 abdominal segment, the back (seen laterally) is about level, each 

 segment rising for four-fifths of its length, and then falling rather 

 suddenly in the posterior fifth to the incision. The colour is a deep 

 apple-green, in only one or two specimens having enough brown to be 

 called somewhat olive, but enough to suggest that variation might 

 extend to a larva being as brown as in previous instar. The "slopes" 

 are closely studded with the light points of the hair-bases, giving the 

 green a darker tint when magnification enough is used to separate the 

 light points, which affect the general effect when not individualised. 

 They are a little irregular in disposition, but obviously tend to be in 

 about ten vertical rows on each segment. Each segment has three 

 paler stripes on its slope, obliquely downwards and backwards ; the 

 lowest contains the spiracle, the upper is further from the dorsal 

 flange than the stripes are from each other. The brown (rich and 

 velvety) is very narrow behind, except where it expands in a large 

 paler escutcheon on the 7th and 8th abdominal segments, and gets 

 broader forward — 0-2mm. on the 6th abdominal, 0-5mm. on the meso- 

 thorax; it is bordered by a fine line, white, or yellowish-white. The 

 prothoracic plate, about 0'7mm. from outer to outer angles, is wholly 

 brown like the dorsal plain. The lateral flange-line is veiy distinct 

 and obvious, of a yellow that is almost white. The head is small, 

 black, shining. The underside is pale green, of a rather sickly, slightly 

 olive, tone ; the legs have their chitinous portions shining black. The 

 hairs are now very numerous, and it would not be hopeful to decide which 

 of five or six hairs might be taken to represent the seta of tubercle i. 

 The hairs all appear to be of light tint, or colourless, but a very decided 

 colour effect, of which practically no trace exists in the previous instar, 

 is produced by the hair-bases and skin-points being nearly black in 

 some places, nearly colourless in others; the lenticles are nearly always 

 dark. The complication of colour and form of hairs and hair-bases 

 with different areas is so great, that no description of moderate length 

 would meet it. Some faint approximation, therefore, must be 

 attempted. First the dark dorsal band of the larva is not probably 

 caused but reinforced by the skin-points along it being black, and the 

 hair-bases also. The hairs here are two to four in the width of the 

 band, more when the band is wider. The hairs are very short, 



