24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 63 



odors scarcely moved when touched with a pencil. These were dis- 

 carded and the flagella of the others were cut off. The 25 used 

 in these experiments gave a reaction time of 3.09 seconds which is 

 0.66 second greater than the same reaction time for normal hornets. 



In conclusion under this head it is seen that about four-fifths of 

 the writers cited advocate the view that the antennae are the seat of 

 the organs of olfaction. Most of these observers have not said 

 whether the mutilated insects that they used were normal. The inac- 

 tivity or state of rest of many of these speciments indicates abnor- 

 mality. In regard to Miss Fielde's ants, only 40 per cent recovered 

 from the effect of the shock and in all probability all of these were 

 more or less abnormal. When the antennse of ants, hornets and bees 

 are mutilated in the slightest degree, as ascertained by the author, 

 the insects are more or less abnormal. The results obtained by using 

 any insect with mutilated antennse are, therefore, in all probability 

 more or less erroneous. Judging from the author's experiments there 

 is no reason to assume the presence of the olfactory organs in the 

 antennse, because the differences in reaction times between the reac- 

 tion times of the mutilated insects and those of unmutilated ones 

 may be attributed to the abnormality of the insects which is probably 

 always caused by the operations. At most it can be claimed only that 

 the antennse may assist in the receiving of odor stimuli. 



Since the organs in the antennse of ants, hornets and bees, and 

 probably all insects, fail to receive most, if not all, odor stimuli, the 

 true olfactory organs must be looked for elsewhere. 



VARIOUS STRUCTURES ON THE ANTENNA AS OLFACTORY 



ORGANS 



Before entering into a discussion of the antennal organs of insects, 

 a brief description illustrated with drawings of the antennas of the 

 honey bee and their organs will first be given. 



The antenna of the bee consists of two portions : the proximal 

 part, called the scape, and the distal portion, the fiagellum. Each 

 portion is more or less cylindrical in shape. The scape consists of a 

 single long, slender joint, while the flagellum consists of 11 short 

 joints in the worker and queen and of 12 in the drone. 



When an antenna is examined under the microscope with a strong 

 transmitted light its surface is seen to be covered with small bright 

 spots and also various kinds of hairs. In order not to overlook any 

 of these peculiar structures, several pairs of these appendages from 

 young bees just emerged from their cells were removed and perma- 



