June, 1014. 



American Hee Jiournal 



£<•/' 



Bri) 20 



Fig, 3.— Side view of sting of a worker-bee with its accessory parts, showing location 

 groups of olfactory organs as indicated by the numbers. 



and wiiitergreen, honey and comb, pol- 

 len, flowers of honeysuckle, leaves and 

 stems of pennyroyal, spearmint and 

 sage, and bee stings. After testing 

 many workers, queens and drones, 

 witli these odors it was found that they 

 have an acute sense of smell. Drones 

 smell slightly better than workers, and 

 workers smell considerably better than 

 . queens. 



To study the behavior of workers 

 with mutilated antennas, and to see if 

 the antenn;e carry the olfactory or- 

 gans, the following experiments were 



performed : One antenna of each of 

 many workers was pulled off. Thus 

 mutilated bees are not entirely normal 

 in behavior. They live only two-thirds 

 as long as unmutilated ones, and seem 

 to smell one-half as well as normal 

 workers. Workers with one antenna 

 pulled oft' and with two to eight joints 

 of the other one cut off are still more 

 abnormal in behavior and respond less 

 slowly to odors. Workers with both 

 antenn:e pulled off, cut off, covered 

 with shellac or celloidin are entirely 

 abnormal in behavior and live less than 



Por3 



PorW 



,PorB/^r 



~yC/}M 



Por/Jp 



!'FiG. 4 —Group 6 of olfactory organs from hind leg of a worker-bee, showing the external 



appearance, highly magnified. 



one day. They fail to respond to all 

 odors. The antenn;c of 95 workers 

 were burnt off with a red-hot needle. 

 These workers were also abnormal 

 and lived only 17 hours on an average. 

 Seven of them which lived longest 

 were tested with odors. They respond- 

 ed one-half as rapidly as normal work- 

 ers. The antenn;c of many workers 

 were covered with liquid glue. Twenty- 

 one were obtained which were fairly 

 normal in behavior, but they lived only 

 24 hours on an average. They re- 

 sponded to odors practically as well as 

 unmutilated workers. 



From the preceding experiments it 

 is evident that bees with mutilated an- 

 tenn;L' are not normal, and that their 

 slowness in responding to odors or 

 their entire failure to react when tested 

 is due to the injury caused by the muti- 

 lation. It seems, therefore, that the 

 antenn;c have nothing to do with the 

 sense of smell. Since bees have an 

 acute sense of smell, and as the an- 

 tennae do not carry the olfactory or- 

 gans, we must look for them elsewhere. 



A few years ago the writer described 

 some organs found on the appendages 

 of spiders. It was proved experimen- 

 tally that these are olfactory organs. 

 After failing to prove that the antenn.-e 

 of bees carry the olfactorv organs it 

 was only natural to examine these in- 

 sects to see if they have organs similar 

 to the olfactory organs of spiders. At 

 once the same organs were found 



Looking at Figs. 1, 2 and .3 it is 

 easily seen where the olfactory organs 

 are located. Groups 1 to 6 lie on the 

 bases of the wings as indicated by the 

 numbers. Groups li to 18 lie on the 

 legs. Groups 19 to 21 lie on the sting 

 (Fig. 3). The same organs are found 

 on all mouthparts, but they are not 

 discussed in this paper. The antenna; 

 of the bee do not carry any of these 

 organs. 



Drones have an average number of 2(304 

 olfactory organs, 606 which lie on all six 

 legs and 1998 on all four wings. Work- 

 ers have an average total number of 

 2:i(i8 olfactory organs, 100 of which lie 

 on the sting, (j,58 on all six legs, and 

 1510 on all four wings. Queens have 

 an average total number of 1860 olfac- 

 tory organs, 100 of which lie on the 

 sting, 450 on all six legs, and 1310 on 

 all four wings. Those on the legs are 

 rather large, but those on the wings 

 and stings are quite small. 



Under the microscope these organs 

 appear as bright spots. At the first 

 glance they resemble hair sockets (Fig. 

 4, For ApHr) from which the hairs have 

 been pulled, but after a closer examina- 

 tion a striking difference is usually 

 seen. Each bright spot is surrounded 

 by a dark line, the pore wall (Figs. -f 

 and .5, PorW). Outside this line the 

 chitin or "skin" (Fig. 4, PorB) may 

 be light or dark in color, but inside the 

 line the chitin (Figs. 4 and 5, ChL) is 

 almost transparent, and at the center 

 there is an opening, the pore aperture 

 (Figs. 4 and 5, Por.'^p). 



In order to study the internal anat- 

 omy of these organs, pieces of the ap- 

 pendages bearing the groups were 

 "pickled " in a special fluid, and these 

 pieces were cut crosswise into many 

 extremely thin slices called sections. 

 These sections were mounted on strips 

 of glass, called microscopical slides, 



