466 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. 



ably serves as a secondary sexual purpose, but in other carnivores, 

 such as the otter, badger, wolverine, mink, martin, ferret, ermine, 

 weasel, and skunk, the scent may be far from mild, and in many cases 

 is used either as a means of defense or offense. 



The present writer has described a special organ for producing 

 odors in the honeybee. It consists of many tiny glands which empty 

 their secretion into the folded articular membrane between the fifth 

 and sixth abdominal segments on the back of the bee. Specially 

 devised experiments showed that the secretion was the source of the 

 individual, family, and sexual odors. 



Scent-producing organs have already been found in most orders 

 of insects and probably all insects have some way of producing 

 odors. The known organs vary widely in structure; the simplest 

 type consists of many tiny glands widely distributed over the entire 

 body, and the most highly developed type is much more complicated 

 than that found in the honeybee. 



The present writer determined from his own experience that the 

 human nose can be trained to recognize a number of characteristic 

 odors pertaining to the honeybee. At the beginning of his experi- 

 ments he was able to distinguish the hive odor (the smell of the bees 

 in the hive, collectively), the brood odor (the smell of the larvae and 

 pupse, fig. 5, B-D (pi. 1)), the honey (A) odor, the pollen or bee- 

 bread (E) odor, the wax (./) odor, and the odor coming from the bee 

 sting. After a few months' practice he was able to recognize the 

 three casts of bees (figs. 1-3) — queens, drones, and workers — merely 

 by smelling them. 



Old workers constantly give off the characteristic bee odor, and 

 when seized they emit another distinct odor which comes from the 

 poison ejected through the sting. No difference between the odor of 

 a guard (fig. 5, / (pi. 1)) and that of a fanner (G) could be dis- 

 tinguished ; the odor from each closely resembles the hive odor ; that 

 is, the odor which comes out of a hive when the hive cover is removed. 

 A worker carding pollen gives off besides the bee odor another odor 

 which comes from the pollen. 



The younger the workers the less pronounced is the bee odor emitted. 

 To the human nose the odor emitted by nurse bees (fig. 5, F (pi. 1) ) 

 and wax generators {II) is much less pronounced than is the odor 

 from old workers. 



Workers just emerged from the cells have a faint sweetish odor, 

 but lack the characteristic bee odor, and workers removed from the 

 cells just before they begin cutting their way out emit a fainter sweet- 

 ish odor. 



Old queens have a strong, sweetish odor, while the odor from queens 

 just emerged from their cells is much less pronounced. The queen 



