NO. 2 RECOGNITION AMONG INSECTS McINDOO 21 



old bees and young ones used in this set of experiments were not 

 sisters, and the lack of a hive odor being- carried by the young ones 

 is probably the chief reason why they were received hostilely, rather 

 than to attribute the hostility to a strange family odor. 



As already described on page 7, 50 workers from hive No. 38a 

 were placed in each of wire-screen cases Nos. i to 3 ; 50 from 

 hive No. 38b into each of wire-screen cases Nos. 4 to 6; 50 from 

 hive No. 49 into each of wire-screen cases Nos. 7 and 8; and 50 

 from hive No. 29 into each of wire-screen cases Nos. 9 and 10. It 

 will be remembered that all the workers in hives Nos. 38a and 38b 

 were daughters of the same queen and that each new colony had 

 formed a new hive odor before the workers were put into these cases. 

 After a confinement of three days in the wire-screen cases the hive 

 odor carried by the bees from their hives had disappeared, and as 

 already stated each individual worker is constantly throwing off an 

 odor which is slightly different from the odor emitted by any other 

 worker, whether that worker be a sister or alien bee. When sister 

 workers in cases Nos. i to 3 were mixed, no hostility was exhibited, 

 because the individual odor of each sister possesses a family charac- 

 teristic which is common to all the workers of the same queen and 

 which is inherited from that queen. The family characteristic may 

 be called the family odor, although it is only a part of the individual 

 odor. The same interpretation may be used to explain why sisters 

 in cases Nos. 4 to 6 did not attack each other when mixed ; likewise 

 why sisters after being confined three days in cases Nos. i to 6 did not 

 attack each other when mixed. In these tests the two different hive 

 odors had disappeared and it seems only reasonable to think that the 

 bees recognized each other as friends by means of the family odor. 

 The reason why sisters in cases Nos. 7 and 8, or those in cases Nos. 

 9 and 10, did not fight when mixed may possibly be attributed to the 

 family odor. When alien workers from cases Nos. 9 and 10 were 

 mixed with those in cases Nos. i to 6, or with those in cases Nos. 7 

 and 8, instead of much hostihty being exhibited, the bees fought 

 each other only lightly. This fact may be explained by the view that 

 they recognized each other as strangers by means of the family odor, 

 which in the daughters of one queen is only slightly different from 

 that in the daughters of another queen. 



5. QUEEN ODOR 



On June 27 at i o'clock, 20 workers from a frame of hive No. 69 

 were put into each of the glass observation cases Nos. i and 2; 



