NO. 9 OLFACTORY SENSE OF INSECTS McINDOO I7 



ants. From these experiments he conchides that the antennae are the 

 organs of smell, but he thinks that the sense of smell in insects is very 

 dififerent from that sense in the human species. He regards it as a 

 kind of feeling or smelling at a great distance by some process now 

 entirely unknown. 



Layard ( 1878) relates the experiments of a certain French natural- 

 ist who immersed a long-snouted weevil in wax so that it was covered 

 all over except the tip of the antennae. When tested with oil of 

 turpentine it became violently excited and endeavored to escape. 

 Another had only the tips of its antennae coated with wax, and neither 

 turpentine nor any other strong-smelling substance affected it. From 

 this he infers that the organ of smell is present in the tips of the 

 antennae of weevils. 



Slater (1878) says: 



That wasps have an acute scent and seek their prey or their food by its means, 

 will be generally admitted * * *. When a wasp is flying it keeps its antennae 

 advanced and extended, so as to be in the most favourable position for receiv- 

 ing an impression from odoriferous substances. 



Chatin ( 1880) states that when one brings a needle wet with ether, 

 creosote, essence of wild thyme, or clove oil near the head of a bee it 

 moves its antennae, vibrates them vigorously, and directs them away 

 from the odorous substance ; if one repeats the same experiments 

 near the spiracles no such movements are manifested. Also, when 

 the antennae are cut off no responses occur. 



Lubbock (1882) experimented with a large female ant. He placed 

 a feather of a pen almost against the antennae of this ant without it 

 moving in the least. Next he dipped the pen in essence of musk and 

 repeated the experitnent. The antennas were at once retracted. With 

 a second ant he used essence of lavender and observed the same 

 results. Many more of his experiments indicate that ants have a 

 highly developed sense of smell. 



Porter (1883) experimented on a butterfly with a piece of gum 

 camphor on the end of a broom straw. He says : 



Whenever I put the camphor end near to its head and mouth parts, it would 

 begin to struggle with all its might to get away from the fumes of the 

 camphor; thus showing not only that it disliked the smell of camphor, but 

 also that it did not smell with its antennae. After experiments have shown the 

 same thing of other insects. 



This butterfly was affected little, if at all, by the extirpation of its 

 antennae while some humble bees become very sick after the loss of 

 their antennae ; they, however, recovered after awhile. Some other 

 humble bees are not affected at all by such an operation. 



