308 Mr. Voulton's further notes upon tJie 



lots, fed respectively upon lilac and privet. I also fed a 

 detachment upon asli, but the larva did not thrive. In 

 the fifth stage the difference appears, and is quite 

 obvious, although much less so than that of *S'. ocellatus. 

 An attempt has been made to show the effects of this 

 experiment in fig. 7 a (Hlac) and b (privet), natural size 

 (Plate VII.). This phytophagic efiect is also protective, 

 for the under sides of privet leaves are of a yellower 

 brighter green than in the case of lilac, and tlie total 

 effect of the two bushes is in the same direction, 

 especially when looked at from a little distance. The 

 difference is made by texture rather than colour. The 

 protective nature of the two colours is also very apparent 

 when the larva are found upon the bushes. 



(8) S. 2)opuli. — There are very great differences in the 

 ground colour of these larvae, quite equal to those of 

 S. ocellatus, but it is not known whether there is any 

 relation with the food-plant. The two chief varieties 

 are similar to those of S. ocellatus, a bright yellowish 

 green and a very white bluish green. I feel sure that 

 many years ago I found the latter variety with a blue 

 horn, and so resembling S. ocellatus that they could not 

 be distinguished for certain (until pupation). S. populi 

 is occasionally found upon various species of Salix, and 

 this year I have come across one upon S.Bahylonica find 

 one upon a tree evidently allied to S. cinerea. Both 

 larvae were light yellowish varieties, and this would be 

 the tendency of the food-plants in the case of *S'. ocellatus. 

 On the other hand, the larvae bred from the same batch 

 of eggs may vary greatly, even if fed upon the same 

 plant. During the past summer Mr. A. Sidgwick proved 

 this, poplar being the food used. It is very likely that 

 further work upon this larva may throw light upon the 

 case of S. ocellatus. It will be especially interesting to 

 note the relation of the red spots (which are more 

 common and more developed in this species than in 

 ^S". ocellatus) to the ground colour. I believe that in this 

 species the spots have no relation to any particular 

 shade of ground colour. I certainly remember yellowish 

 larvae with the spots, and in my paper in the ' Trans- 

 actions ' of this Society (Part I., April, 1884, Plate I., 

 fig. 2) an extremely pale larva is figured with the spots 

 developed to a very remarkable extent (I am indebted to 

 the kindness of Mr. G. C. Bignell for the loan of the 

 drawing which was figured). These facts would favour 



