146 Miss Elizabeth Bridges upon colour-relation between 



(/) Black twigs of oak with pink spots painted on 

 them : bluish-black larvae. 



(g) Slips of white wood painted with scarlet squares 

 (length of side about 2 mm.) : cream-coloured larvae with 

 faint smoky pattern (slightly darker than in (d)). 



It will be noticed that the twigs painted in geometrical 

 patterns produced no corresponding effect. The results 

 of all the experiments seem to show that although the 

 individual larvae and pupae are able to conceal them- 

 selves very effectually among surroundings to which the 

 species is accustomed, they are powerless to effect any 

 appropriate adaptation to an " artificial " environment. 



TABLE IV. 



V. Notes on the apparatus used. 



The larvae were kept in clear glass cylinders or lamp 

 shades, varying from 8 to 10 inches in height, and from 

 3 to 5 in diameter. The tops were covered by white 

 muslin or calico. The floors were of wood covered with 

 white paper : a hole in each floor allowed the stems of the 

 food-plant to pass through into a jar of water. As the 

 larvae became larger, some were transferred to other 

 cylinders, so that they were never crowded. 



The pupae which were not left in their original environ- 

 ments were tested in cardboard compartments (about 



