EXPERIMENTS ON PROTECTIVE COLORATION 483 



latter, as it dropped it once before eating it. It then turned back and 

 took the moth from the bark. 



Experiment 23. Figures Ifi and 4^. One Gryllus was placed on 

 ashes and one on a mixed background of charred and uncharred wood, 

 the latter combination presenting a close resemblance, and the former 

 a good contrast. The grackle immediately dropped to the ground 

 and began feeding. It soon went to the backgrounds, passing nearer 

 the charred wood, but taking the cricket on the ashes. It then turned 

 'and walked over the charred wood, passing directly over the cricket 

 upon it, but apparently not seeing it. 



Experiment 24- Same as Experiment 23, except that in the former 

 both crickets were probably in shadow,-^ while in this experiment they 

 were in the sun. The grackle immediately dropped from its perch 

 to the ground and approached the backgrounds about midway be- 

 tween them, paused a moment and seized the cricket on the ashes, 

 after which it turned and took that on the wood background. The 

 prompt approach of the grackle to the backgrounds in this experiment 

 apparently indicates that it realized that food had been prepared for 

 it there. Its attention however was not I believe attracted to one back- 

 ground more than to the other in the preparation of the experiment. 

 Its pause for a moment after reaching the backgrounds, and the prompt 

 seizure of both insects suggests that both were seen as it approached, 

 and that it was a matter of chance, or possibly of some individual 

 preference on the part of the bird as to which was taken. 



Experiment 25. Figures 51 and 53. One green Melanoplus was 

 placed on grass and one on charred wood. For three-quarters of an 

 hour the insects were untouched, although the grackle several times 

 went to within a short distance of the backgrounds. For seven min- 

 utes the observations were discontinued. Soon after resuming them, 

 the grackle once again approached to within about 3 cm. of the back- 

 grounds but did not feed. Then it again approached, coming nearer 

 the charred wood, from which it seized the insect, and then immediately 

 took one from the grass. The charred wood combination presented 

 the greater contrast. That the insects were left untouched for so 

 long a time in this experiment, because of the bird not being hungry, 

 is improbable, as it was pecking at objects on the bottom of the cage 

 during this time, and when^one insect was finally taken the other was 

 immediately taken also. Further, in the following experiment (26), 

 the grackle took the insects very soon after the experiment was started 

 and within about ten minutes of the last feeding (in Experiment 25). 



Experiment 26. Same as Experiment 25. The grackle immediately 

 dropped to the ground and approached the backgrounds. It turned 

 back for a moment and then re-approaching between the two back- 

 grounds, took the insect on the charred Avood and immediately after, 

 that on the grass. 



Experiment 27. Figures 49 and 51. One green Melanoplus was 

 placed on a mixture of grass and straw (lengthwise on a straw so as 



-* On this point my notes are uncertain. 



