NO. 2 RECOGNITION AMONG INSECTS McINDOO 17 



their sister guards and when a guard from the alighting board of their 

 own hive was introduced into each case containing workers from 

 the cages, ii guards were attacked Hghtly and nine were attacked 

 quite forcibly. 



The experiments with bees in the boxes and cages further sub- 

 stantiate the view that a new hive odor may be formed in three days 

 when middle-aged bees are confined in a container having tight- 

 fitting walls, and that the hive odor must be composed of a combina- 

 tion of all the odors emitted from the individual bees. Also, when 

 bees are confined in a container having wire-screen sides, no hive 

 odor can be formed, because the air passing freely through such a 

 container carries away the individual odors just as fast as they are 

 given off by the bees. Furthermore, sister workers are hostile to 

 sisters of any age if the latter are mostly devoid of a hive odor, or 

 if they carry a hive odor which is slightly different from the hive 

 odor of the former. Several workers just emerged from their cells, 

 if confined in a close-fitting case, may accumulate a hive odor by the 

 fifth or sixth day. This hive odor differs enough from that formed 

 by other sister bees of the same age in another similar case to produce 

 hostility when the sisters from the two cases are mixed. 



To ascertain if workers confined singly for a few days in close- 

 fitting cases are able to form hive odors, and to furnish another 

 proof, if possible, whether a hive odor is nothing more than a com- 

 bination of the various individual odors, the following experiments 

 were performed: Nineteen small triangular observation cases were 

 constructed. Two of the sides were 5 inches and the third side was 

 4 inches in length. The depth was | inch, the top was glass, and the 

 bottom was wire screen. 



To be sure that young workers bearing as little hive odor as 

 possible might be used, half of a comb containing just emerging bees 

 was removed from hive No. 19 and was placed in one of the cages 

 described on page 15. Five days later most of the bees had emerged 

 and two days after this date one of these young workers was intro- 

 duced into each of the 19 cases. When put into these cases they had 

 been emerged probably four or five days on an average and were 

 sufficiently old to possess the characteristic bee odor. A small piece 

 of candy and a small piece of cotton wet with water were also put 

 into each case. A thick cloth was spread out on top of a table and 

 these cases were put side by side on top of this cloth, then another 

 cloth was spread over the tops of the cases. After a confinement of 

 four days in these cases, five of the bees had died, and the remaining 



