NO. 9 OLFACTORY SENSE OF INSECTS MclNDOO 9 



treiiiely tine pencil brush \vet with tlie same oil near the eyes, anteini.e, 

 proboscis and mouth cavity. The only response oljservcd was when 

 the brush came near the mouth cavity. He obtained the same result, 

 only more pronounced, when oil of origanum was used. The mouths 

 of several bees were filled with Hour paste and when this was dry 

 they were released. Honey, turpentine and oil of cloves, either in 

 fixed or volatile alkalies, did not produce any response. 



ERIPHARYNX AS SEAT OF OLFACTORY ORGANS 



\\'olfif (1875) found many peculiar hairlike organs on the epi- 

 pharynx of the honey bee ; each organ consists of a small cone with 

 a pit in the summit bearing a small hair. He regarded these cones 

 as having an olfactory function and believed that the mandibular 

 glands pour a liquid upon the surface of the epipharynx which keeps 

 these cones moist and capable of absorbing odoriferous particles. He 

 explained the inhalation of these particles into the preoral cavity as 

 brought about through the contraction of the air sacs situated near 

 the mouth. 



Harting (T879), ^'^ discussing Wolfif's olfactory organs, inferred 

 that Woltt tried to homologize the epipharynx with the nose of higher 

 animals whereas there is not the slightest reason for such an 

 homology. 



To determine whether the mouth cavity and the epipharynx are 

 the seat of the olfactory organs, the author repeated Huber's experi- 

 ment of filling the mouth cavity with flour paste. With the aid of a 

 small pencil brush the mouth cavities of 20 worker bees were thus 

 filled. When the paste had become perfectly dry, the bees were put 

 into observation cases. They seemed otherwise entirely normal, but 

 lived only 7^^^ days as an average, whereas unmutilated workers in the 

 same cases lived 9 days and 3 hours. When tested with the oils of 

 peppermint, thyme and wintergreen, their average reaction time was 

 2.68 seconds. The average 'for the same odors with normal workers 

 was 2.64 seconds. It would seem that neither the buccal cavity nor 

 the epipharynx has anything to do with olfaction. 



PALPI AS SEAT OF OLFACTORY ORGANS 



Lyonnet (1745) thinks that the palpi should be considered as the 

 organs of smell rather than those of taste. 



Bonnsdorf (1792) and Knoch (1798), according to Ferris (1850), 

 regarded the palpi as olfactory organs, but Knoch believes that the 

 maxillary palpi only are for smell, while the labial palpi are for taste. 



