466 R. T. YOUNG 



grass. One bird now picked a Melanoplus from the grass and then 

 passed to the straw and picked one of the same from the latter. 



Two of each species were now left on the straw and four of each 

 on the grass. A bird went first to the grass where a Melanoplus jumped 

 directly before it and fell under a grass blade. The bird then passed 

 to the straw and took one Melanoplus. 



This experiment was not observed further for some time, when it 

 was found that all of the insects had been eaten except three or four 

 Xyphidium on the grass. ^^ Summed up the results of this experiment 

 are as follows: During the period of observation five"^- Melanoplus 

 were taken from the straw, and one from the grass. After this one 

 Melanoplus and two Xyphidium were taken from the straw and four 

 Melanoplus from the grass. 



Experiment 4- In this experiment the position of the insects was 

 reversed they being placed ventral side up. A yellow and dark gray 

 surface in the case of Melanoplus, and a green and straw colored 

 surface in that of Xyphidium was now exposed to the view of the 

 birds. The order of resemblance to my eye in this case was as follows: 

 Xyphidium — grass, Melanoplus — straw, and Xyphidium — straw, Melan- 

 oplus — grass (the two latter about equal). ^' One bird passed first 

 to the straw and seized a Xyphidium. Four of each species were 

 now left on the straw and five of each on the grass. A bird now passed 

 to the straw first (from the side of cage nearest to the latter) and took 

 a Melanoplus therefrom. Five of each species were now placed on straw 

 and grass respectively. A bird passed to the straw (from the side 

 nearest thereto) and took one Xyphidium and one Melanoplus. Four 

 of each species were now placed on straw and five of each on grass. A 

 bird flew over the straw to the grass and took a ]\Ielanoplus. Four of 

 each species were now left on both straw and grass. A bird went to 

 the straw and took one of each species. Three of each species were now 

 left on straw and four of each on grass. One bird now passed to the 

 straw and took two Xyphidium and one Melanoplus. The straw- 

 was now removed and five of each species were left on the grass. In 

 three feedings from the grass four Melanoplus and no Xyphidium were 

 taken, the number of each species being kept constant after each feeding. 



Summation of the results of Experiment 4. Before removal of 

 straw five Xyphidium and four Melanoplus were taken from it and 



" The exact number left on the grass untouched during this period I am not 

 certain of, as they had all fallen more or less among the blades of grass and one 

 of them may have been concealed by the grass from the first. 



12 One of these was replaced making a total of six instead of five Melanoplus 

 placed on straw during this experiment. 



13 It must be remembered in this, as in the preceding experiments, that the 

 surface exposed to the birds' view from a position on the floor of the cage was 

 somewhat different from that exposed to the view of an observer looking down 

 onto the floor from above. 



