SESIA STELLATARUM. 13 



a change of skin (Reaumur). The larva is light or dark green or 

 brown, densely covered with raised white dots. When fullgrown, 

 it is 50mm. — 60mm. long. At each side of the dorsum runs a 

 longitudinal white or reddish line, above the legs a light or dark 

 yellow stripe, above which stand the black spiracles. A brown 

 stripe in the middle of the dorsum may be either present or 

 absent. The horn is bluish-green, brown, or blackish, at the 

 apex either red-brown, yellowish, or black. Head of the same 

 colour as body, rough, shagreened. Before pupation the larva 

 becomes dirty brown-red (Bartel). 



Variation of larva. — When rearing the larvae of this species 

 ab ovo, and also when rearing captured larvae that have been taken 

 very small, I find that after the second moult, the larvae frequently 

 turn a dark green in colour, almost black, but are quite healthy 

 and produce perfect moths, although I do not take this aberration in 

 the wild state ; if it does occur wild it must be very rare (Ransom). 

 Shortly before spinning up, but not in many cases before the larva 

 has finished feeding, the whole skin area, with the exception of the 

 coloured lateral stripe and the shagreen spots, darkens to a livid 

 reddish-purple hue, against which the stripes and shagreen spots 

 show up with great distinctness. This colour change (analogous 

 with that which occurs in the larva of Mimas tiliae) gives the larva 

 a repulsive snaky appearance, and the peculiar jerky method ot 

 crawling greatly aids in the sinister appearance of the larva. The 

 description of the full-grown larva (antea, pp. 11-12) applies to by far 

 the greater proportion of some 50-60 larvae collected in 1900, but 

 a few examples showed striking variation in the ground colour. 

 One larva had the ground colour of a much darker and more vivid 

 green than usual, and a strongly-marked dark purple, almost black, 

 mediodorsal stripe ; the subdorsal stripe cream-coloured instead of 

 white, strongly bordered above by the same dark purple tint as the 

 mediodorsal, the spiracular band similarly bordered both above and 

 below ; a narrow dark medioventral stripe also present ; the dark 

 borders gave the pale bands a much greater intensity. Another 

 larva varied somewhat similarly, but the darkening had progressed in 

 this example until the whole ground-colour was dark olive-green, with 

 the exception of a broad vivid green band on either side of the dark 

 purple mediodorsal band. This form was the most handsome 

 observed, the dark purple mediodorsal band with the bright green on 

 either side making a striking contrast, whilst the sombre olive ground- 

 colour of the subdorsal and lateral areas also showed up, in fine 

 contrast, the subdorsal and spiracular bands and white shagreen 

 spotting. One or two larvae were even more extreme in the darkening, 

 the whole ground-colour being of the darkest olive-green, tending 

 to purplish in places : the head olive-brown (Bacot). Buckler 

 figures (Larvae, etc., ii., pi. xxvi., figs. 2, 2a, zb) three different 

 forms of the adult larva: (1) Purplish-red dorsally and laterally 

 to the bluish subdorsal line. (2) Brownish-grey with a dark brown 

 subdorsal line. (3) Green, with a white subdorsal line. Sich observes 

 (Ent., xxv., p. 288) that he found a larva at Westgate, in July, 1892, 

 of the dark-green form, which had the caudal horn curved down- 

 wards like that of the larva of Sphi?ix ligtistri ; the imago produced 

 was rather dark, but otherwise normal. 



