lepidopterous larvae and 'pup(B. 153 



settlement of this question would be one of the most 

 interesting results of the investigation of the ontogeny. 

 The ground colour is known to be greener in the 

 penultimate stage, while it is not uncommon to find 

 individuals in the last stage with a green ground colour 

 (the common form being, of course, yellow. See the 

 English translation of Weismann's 'Essay,' p. 323). It 

 seems certain therefore that the ground colour is green 

 in all stages except the last ; the newly-hatched larva 

 being probably of a transparent yellowish tint until after 

 its first meal, while the head may be greener, as in the 

 young S. ligmtri, which has just emerged from the egg. 

 The well-marked dimorphism probably arises in the 

 penultimate or in the last stage (in ClKerocampa elpenor 

 it takes place in the last stage, occasionally in the fourth ; 

 in C. porcdlus it appears regularly in the fourth stage, 

 occasionally in the third. See translation of Weismann's 

 'Essay,' pp. 181 and 186). 



Since writing the above I am informed by Professor 

 Moseley that he has found the larva before its last 

 stage, and that he distinctly remembers that it was 

 shagreened all over like a Smerinthiis larva. 



4. The relation of the colours of the larva of 

 Sphinx ligustri to those of its food-plants. — On 

 August 11th, 1885, I found two full-grown larvae of this 

 species upon a tree of the wild guelder-rose upon an 

 island in the Eiver Cherwell, near Oxford. As the food- 

 plant was new to me, I carefully observed the larval 

 colours which were produced after feeding upon it. The 

 ground colour was bright green, like that caused by 

 privet, but the coloured borders to the stripes were of a 

 very bluish lilac, and rather duller than in the larvae 

 found upon the latter plant. 



On August 1st, 1885, I found a larva of S. ligustri 

 upon privet in the Oxford University Parks ; it was at 

 the beginning of the last stage, and possessed the bright 

 colours which follow the use of this food-plant. I fed the 

 larva upon lilac during the last stage (August 1st — 12th), 

 and there was a gradually increasing change towards the 

 duller colours which are always caused by lilac, which, 

 however, were not ultimately produced to such an extent 

 as is seen after feeding the larva upon this food-plant 

 for their whole life. 



TRANS. ENT. SOC. LOND. 188G. — part II. (JUNE.) M 



