SATURNIA PAVONIA. 325 



There are certain directions in which variation of the larva occurs, 

 on which detailed information would be exceedingly useful, e.g., the 

 maintenance of characteristic features of any of the earlier stadia in 

 individuals that have reached the adult stage, etc. Newnham says 

 (Ent. Rec, ii., p. 199) that some larvae have broad velvety rings 

 around each segment, in others, they are reduced to small rings 

 around each tubercle ; whilst the tubercles themselves offer many 

 variations, bright yellow (the commonest form), orange, pink, white, 

 black and purple, the three last-named forms being the rarest. 

 Scharff notes an adult larva near Lough Bray, in the Wicklow 

 mountains, in August, 1894, which was " entirely black, with the 

 exception of the yellow tubercles, the green ground colour being 

 reduced to a frontal triangular patch and two lateral streaks on the 

 head, a pair of dorsal spots on the mesothorax and the two spots, 

 on either side of each abdominal segment, which together form 

 a broken spiracular line." Bacot observes {Ent. Rec, iv., p. 199) 

 that he " obtained a brood of young larvae in June, 1892, on a 

 whitethorn hedge, near Thundersley ; from a $ and ? reared from 

 these larvae, a batch of ova was obtained in 1893, the larvae hatching 

 in about 20 days. After their first moult, the larvae varied very 

 widely, some of them being entirely green or pale yellow without 

 any black, some remaining (until their third moult) quite black, 

 with the exception of a reddish or brownish stripe along the side. 

 The latter retained a large proportion of black in their coloration 

 until nearly fullfed, while others, exhibiting nearly every grade 

 between these two extremes, could be picked out of the brood. 

 It seems strange that a brood of larvae should vary so widely after 

 their first moult, and yet be so alike (comparatively speaking) in their 

 last stage. The following possible explanation has occurred to me : 

 The larvae until the first moult are quite black, and they feed 

 gregariously until the third moult. When feeding on a hedge or 

 bush they might easily be overlooked, as the eifect of a brood of 

 small black larvae lying close together is to blot out the leaf or 

 leaves on which they are feeding, leaving an apparent opening in 

 the hedge, such as would be obtained if one or two leaves were picked 

 off. If, however, the whole brood retained its black colour as the 

 larvae grew larger, the size of the apparent opening or hole in the 

 hedge would become noticeable, but as they vary in colour, they 

 match very well with the bright green leaves and dark spaces 

 between, in fact, if they cleared a patch of leaves, the larvae would 

 themselves (to a certain extent) present the appearance of the 

 missing foliage. No doubt after the third moult, when they scatter, 

 the bright forms are, as regards colour, by far the best protected." 

 Poulton notes (Trans. Ent.Soc. Loud., 1887, pp. 310 — 312) that 80 larvae 

 received from Norfolk, July 25th, 1885, and found feeding on Spiraea 

 ulmaria, varied in ground colour, in the last stadium, from light bright 

 green to dusky green. The black markings were also very variable 

 in the last stage, being, as a rule, especially small in the bright green 

 larvae ; in some larvae the black rings were incomplete, and were 

 occasionally reduced to a mere black line round each tubercle. 

 The longitudinal black marks, as a rule, only occurred in the dull 

 green larvae. In 76 larvae the tubercles were yellow, varying from 

 orange to lemon-yellow, and the lighter tubercles were generally 



