290 THE EFFECT OF FOOD 



Tortoiseshell) usually feeds upon elm, but that of V. 

 urticce (Small Tortoiseshell) upon nettles. Some 

 larvae were found by Mr. J. A. Tawell feeding upon 

 nettles, and so were considered to be those of V. urtiwz. 

 They were accordingly kept on nettles, but to his sur- 

 prise developed into V. polychloros imagines. " These 

 specimens," records Newman, to whom they were 

 shown, " have a wonderful similarity to urticce, which 

 they do not at all exceed in size; still the colour is 

 nearer to that of polychloros than that of urtictz" The 

 effect of abnormal food on Melitcea artemis (Greasy 

 Fritillary) has been noticed by H. Gross.* By feeding 

 the larvae on honeysuckle, a series of very dark imagines 

 was obtained, which differed both in size and colouring 

 from all other specimens known to him, though these 

 had been derived from very varied localities in Eng- 

 land, Ireland, and Scotland. Again, the quantity of 

 the food supplied may have as considerable an effect as 

 the quality. By mistake some V. io (Peacock butter- 

 fly) larvae, captured by Mr. R. Cox,f were left for sev- 

 eral days without fresh food, and all the dead leaves and 

 stalks were devoured. Nearly all the imagines ob- 

 tained from them were rather small, but they also 

 varied much in the intensity of their colouring, two 

 specimens being very much darker than usual, with the 

 yellow in the costal spot and ocellus much reduced. It 

 seems to me, however, that probably these changes were 

 due rather to the abnormal food devoured by the larvae 

 than to the actual lack of food. 



As regards the larvae of Lepidoptera, the obvious re- 



*The Entomologist, vii. p. 203, 1874, 

 f The Entomologist, ix. p. 58, 



