NO. 9 OLFACTORY SENSE OF INSECTS MclNDOO I3 



Slater ( 1848) firmly believes that the anteniiDe are olfactory organs. 

 He says that the antennae seem to be the real organs for this sense 

 or for a sense closely allied to it. 



According to Dufour ( 1850) both the organs of audition and olfac- 

 tion are found on the antennae. The distal joints, which have a 

 spongy texture, are the ones that bear the sense of smell, for here the 

 odoriferous atoms can fall upon this special texture and the impulse 

 can be transmitted to the cerebral ganglion. 



Claparede ( 1858) asserts that absolutely nothing warrants us in 

 locating in the antennae the sense of hearing rather than that of 

 olfaction or any other function, but he favors the view that the organs 

 of smell are there. 



Donhoff (1861) from various experiments contends that bees learn 

 the location of honey and of the queen through the antennie. He 

 placed a stick near the antennse of a bee and these appendages re- 

 mained quiet. When a stick wet with honey was similarly placed, 

 the bee at once extended these appendages in the direction of the 

 stick. \Mien one places a foul-smelling substance like tobacco juice, 

 near the antennse, the bee moves away. When one places a stick wet 

 with honey or tobacco juice near a bee with amputated antennae the 

 insect shows no response of any kind. He thinks that the olfactory 

 organ was removed by cutting off the tip of the antennae. 



Xoll ( 1869) asserts that butterflies have a fine sense of smell as 

 shown by the way in which they find prepared food when placed in 

 a box covered with screen wire and having only a slit through which 

 these insects may enter. This is shown by the way in which the males 

 are able to find the females. He regards the antennae as the olfactory 

 organs, at least for the male. 



A\'onfor (1874) says: 



That it is the sense of smell which directs the blow-fly to the deposition of 

 the larvae is shown by the fact that she has laid them on stapelias, a carrion- 

 odoured hothouse plant, and on silk with which tainted meat had been covered. 

 Notwithstanding the view of Hicks he considers one of the functions of the 

 antennas as that of smell. 



Fabre (1882) remarks that it is incontestable that insects have a 

 very highly developed sense of smell. Carrion beetles run from all 

 sides to the place where a dead mole lies. H we admit that the seat 

 of smell lies in the antennae he contends that it is difficult to compre- 

 hend how such an appendage of hard chitinous rings, articulated end 

 to end, is able to fulfill the office of a nose. The organization of a 

 true nose and that of the antennae have nothing in common. 



Henneguy (1904) state that the organ of olfaction is probably 

 located in the antennae and the buccal palpi. 



