1893. NOTES ON LEPIDOPTEROUS LARV^. 441 



eating this larva with impunity developed by the action of Natural 

 Selection, after necessity had first driven its ancestors to the attempt. 

 My experiments were made on a less extensive scale than those 

 described by Mr. Beddard as undertaken by Mr. Finn and himself, 

 and are, therefore, perhaps, of less value ; but as far as my experience 

 went I was not at all able to confirm Mr. Beddard's statements as to the 

 " behaviour of animals when offered inconspicuously-coloured " prey, 

 resembling that with which they approached conspicuous forms. I 

 repeatedly gave common green smooth larvae and other species with 

 protective colouration both to the bird and lizards, and invariably found 

 them accepted and eaten without the slightest hesitation, except just 

 after distasteful food. I scarcely think the garden slug, which j\lr. 

 Beddard saw refused by several birds, is a fair example of a pro- 

 tectively-coloured animal treated as if it were inedible. The slime 

 of the slug would be disliked by many animals, and there is evidence 

 from many of the experiments that it was so disliked, since it was 

 only swallowed " after much rubbing on the ground." The shme 

 would seem to be as effectual a protection, apart from all 

 question of colour, against some pursuers as the hairs of the 

 larva of Bomhyx rubi ; the latter cannot be said to be conspicuously- 

 coloured, and yet was refused by all the animals with which 

 I experimented. I did not find a single case of a larva which 

 was both protectively-coloured and smooth being refused by animals ; 

 such larvae were always eaten with avidity. It will, however, be 

 interesting to extend these experiments and note the results carefully, 

 and it is one of the great merits of Mr. Beddard's book that he 

 therein points out so many lines for investigation, and calls attention 

 to many details which are worthy of further consideration. 



With regard to experiments on the colour-relation between 

 certain lepidopterous larvae and their surroundings, the results ob- 

 tained by me were the same as those obtained by Mr. Poulton 

 previously with the same species, except that in one case my results 

 were, perhaps, slightly more definite. 



I reared in different surroundings 19 larvae of Ritmia cratoegata, 

 42 larvae of Catocala niipta, 10 larvae of Catocala fraxini, and 29 ot 

 Mamestra brassica-. Dark surroundings produced in R. cratoegata very 

 dark brown or nearly black larvae, while in green surroundings 

 larvae from the same parent became of varying shades of green or 

 greenish-brown, with touches of crimson exactly corresponding to 

 the red of the thorns and one side of the young shoots of the food- 

 plant. The resemblance to twigs of hawthorn was very perfect, 

 and was heightened by the angular attitude adopted by the larvae 

 at rest. 



For Catocala nupta, dark, green, and white surroundings were 

 used, and the dark surroundings produced darker brown larvae than 

 the green surroundings, while no difference in shade was perceptible 

 between those in srreen and those in white surroundings. Mr. Poulton 



