Vll 



yellowish larvae. The imaginal eye was also olive-green but 

 of a paler shade than that of the larva. Although the blood 

 appeared similar to that of the yellowish-green larvae, physico- 

 chemical differences v/ere probable — accounting for the 

 changed colour of the hypodermis and the orange-yellow hue 

 of the scale pigments on the under surface of the H.W. and 

 tip of F.W. — parts most exposed during pupal development 

 to the action of the blood. 



The utilisation of derived plant-pigments in different ways 

 by different individuals had been proved, not only in species 

 like the above in which the power and its manifestation were 

 hereditary and doubtless germinal in origin, but in species in 

 which it was called forth as a response to stimulus. And in 

 the latter the persistence of the pigments was as great as in 

 the former. Indeed, in an example demonstrated 35 years 

 ago the derived colour of a caterpillar, determined by the tint 

 of the leaves of its food-plant, passed on into the young 

 caterpillars of the next generation. As the record of this 

 result is brief and not very accessible to Entomologists, it has 

 been thought well to reprint it from the Proceedings of the 

 Physiological Society at Oxford on July 2, 1887 (" Journ. 

 Physiol.," VIII, pp.'xxv, xxvi) : — 



" 3. Mr. E. B. Poulton exhibited some ova of Smerinthus 

 ocellatus and of S. popidi, and some young larvae of the 

 former species. 



" The colour of the ova in both species was shown to corre- 

 spond with that of the larval stage of the female moth which 

 laid the eggs ; and the young larvae are also similarly tinged 

 immediately after hatching, although their subsequent 

 appearance is known to be determined by their coloured 

 surroundings. The colour of the eggs and newly-hatched 

 larvae appears to strictly follow that of the female parent, 

 and a similar correspondence was witnessed in the unfertile 

 ova laid by unimpregnated females. 



" These observations render it probable that the chloro- 

 phylloid pigments persist throughout all the stages of one 

 ontogeny and are then handed down to the earliest stage of 

 the next. ..." 



Now that this interesting subject was again being studied it 



