486 Mr. Vonlton's fart Jier experiments upon 



This bright green larva was the single exception found in a lot of 

 34 exposed to dark surroundings (Experiment I.). It is represented 

 upon a twig of Quercus cerris, which serves to show the nature of 

 the conditions employed. It became mature much befoi'e the 

 other larvae, and probably passed through the most sensitive period 

 before the experiment began. Compare its size with that of 

 fig. 10 from the same experiment. 



Figs. 11 and 12. — Two larvie from Experiment II. They had 

 been subjected to dead brown twigs of some species of Salix, the 

 appearance of which is seen in these figures. One larva (fig. 12) is 

 rather lighter and greyer than the other, but the resemblance to 

 the surroundings is very strong ; and no greater divergence occurred 

 between any of these larvas than that shown in figs. 11 and 12. 



Fig. 13. — Three larvae were transferred from the last Experiment 

 (II.), and were exposed to green surroundings (XXVII.) from 

 July 27th to the end of larval life. On Aug. 10th a drawing of the 

 lightest one was made, and is reproduced here. The efi'ect was 

 but slight, the larva being rather lighter and greyer than any in II. 

 It is represented upon a twig of Pojyidas nigra. 



Fig. 14. — A typical result of Experiment VI. is shown in this 

 figure. The posterior claspers of the larva are fixed to a dead 

 brown ivy leaf, thus showing the appearance of the environment 

 with which most of the larvae harmonised well, and from which 

 only one differed considerably. The painting was made about 

 Aug. 5th 



Fig. 15. — A greenish white larva from Experiment XXVIII., 

 resting on one of the white paper spills which formed the environ- 

 ment. The larva was mature when it was painted about Aug. 5th. 



Fig. 16. — A brownish white larva from XXVIII. , also resting on 

 a white paper spiU. When it is remembered that these were 

 examples of the least white larvae in this experiment, the effect of 

 the white spills is seen to be most remarkable. A whitish larva, 

 exhibiting no tendency to brown or green, was selected for 

 painting, but it began to pupate, and altered in appearance before 

 this could be accomplished. 



Fig. 17. — A dark piurplish brown larva from Experiment XXXI., 

 resting on a dark blue paper spill. All the 10 larvae in this set 

 assumed this particular shade of brown. The larva was painted 

 about Aug. 5th. 



Fig. 18. — Abdominal segments 1 to 4 (indicated by numbers) of 

 an intermediate larva, divided along the median ventral line, and 

 spread out flat, as seen from the internal surface. The digestive 

 tract has been removed. The tracheal system is shown on the left 

 hand only. The arrow indicates the anterior direction. The 



