C1MBBX LUTEA. 15 



usually commences on the second body segment, and 

 gets very narrow towards the tail. This stripe is 

 darker at the folds, so that it appears to be made up 

 of lighter squares separated by darker transverse bars. 

 The head is of a pale greenish or greyish-yellow. 

 The spiracles are black, lighter in the centre, and 

 expanded on the lower side. The legs are pale green, 

 with darker claws. 



When young the larva is greenish-white, and, unlike 

 the young of sylvarum, has a small, short dorsal stripe. 



Besides the larva described above, Brischke (1. c., p. 

 239) found others feeding on Salix aurita, which Zad- 

 dach and himself refer to 0. lutea, notwithstanding that 

 they differed considerably from the Salix alba feeding 

 form. The ground colour of the body with these goat 

 willow-feeding larvse is ochre-yellow, orange, or red- 

 dish, and marked with yellowish transverse stripes as 

 well as with greenish-yellow spots. The head is ochre- 

 yellow or reddish. The dorsal stripe is violet and, as 

 in the normal form, is divided into clear spaces. 

 The arrangement and form of the white tubercles and 

 stigmas is the same as in the ordinary type. When 

 young these larvae are clear bluish-green, reddish-yellow 

 on the back, the head is white, and the dorsal stripe is 

 small and dark blue. 



These larvae eject the acid liquid from the lateral 

 pores much more copiously than the others, and they 

 are very difficult to rear, Brischke having only suc- 

 ceeded in rearing two males and one female during 

 fifteen years. One of the males was identical with the 

 black-coloured male of lutea, the two other specimens 

 differed from any form of lutea seen by Zaddach, both 

 being much paler coloured than usual ; but whether 

 they represented merely extreme varieties of lutea or 

 distinct species is a question which cannot be decided 

 from the limited information at hand. If they truly 

 belong to lutea it is certainly a most remarkable case 

 of dimorphism in the larvae. The pale-coloured pair 

 bred by Brischke are to be referred to the var. pollens. 



