THE ABDOMEN, WAX GLANDS, AND STING. 83 



strongly decurved beyond the bulb. The lancets have fewer and 

 smaller barbs than those of the worker, but the two poison glands 

 are well developed (fig. 57, AGl and BGl), while the poison sac 

 (PsnSc) is especially large. 



A number of minute unicellular glands open upon the interseg- 

 mental membrane between the seventh and eighth terga of the ab- 

 domen. These are sometimes called the glands of Nassanoflf, after 

 their discoverer. Nassanoff suggested that they are sweat glands, 

 while Zoubareff thought that they form small drops of liquid said 

 to be excreted by bees during flight derived from the excess of water 

 in the newly collected nectar. Their function, however, has been 

 much more carefully investigated by Sladen (1902), who found that 

 they are scent organs producing a strong odor* even when the part 

 of the back to which they are attached is removed from the rest 

 of the abdomen. He furthermore identified this smell as the same 

 that bees give off when a lot of them are shaken from a frame on 

 the ground close to the front of the hive. Under such circumstances 

 also, as in natural swarming or during the first flights in the spring 

 or after a period of bad weather, bees are well known to produce a 

 peculiar sound called the " joyful hum." Sladen observed that this 

 was produced, in the case of bees shaken before the hive, by those 

 individuals who first found the hive entrance, then by those next to 

 them, until very soon all the others were informed of the location 

 of the entrance and proceeded to make their way in. Also, when a 

 swarm loses sight of its queen, those Hhat find her first set up this 

 " joyful hum " and immediately the rest of the swarm is attracted 

 to the spot. In the springtime the young bees seem to be guided 

 in their flights by this same hum of the old ones. Sladen, however, 

 observing the odor emitted at the same time, thinks that this and 

 not the sound is the real means of information, the sound being 

 simply incidental to the special movement of the wings produced 

 for the purpose of blowing the odor away from the body. He argues 

 that we have no evidence of an acute sense of hearing in bees, while 

 it is well known that they possess a delicate sense of smell located on 

 the antennae. This argument certainly seems reasonable, and we 

 may at least accept Sladen's theory as the best explanation of the 

 function of the glands of Nassanoff. 



