NO. 9 OLFACTORY SENSE OF INSECTS McINDOO II 



seconds, whereas for the same odors with unmutilatcd bees the aver- 

 age was 3.4 seconds. Since these appendages carry several poreHke 

 organs, we may either attribute the 0.6 second difference in reaction 

 time to the view that these appendages really aid in receiving odor 

 stimuli, or to the injury caused by the operation, or to both of these 

 views combined. 



Breithaupt ( 1886) describes some porelike sense organs on the base 

 of the proboscis of the bee. To determine whether these have an 

 olfactory use, the author cut oft' the proboscides of 22 workers. 

 These bees seemed normal in most respects, but lived only 7 hours 

 on an average. When tested with the oils of peppermint, thyme and 

 wintcrgreen the average reaction time was 2.9 seconds, while for the 

 same odors with unmutilated bees the average was 2.6 seconds. We 

 can probably attribute this difference of 0.3 second to the abnormality 

 of the mutilated bees. 



Janet (1911) describes a sense organ in the mandible of the honey 

 bee which he thinks may have an olfactory function. To ascertain 

 this experimentally, the mandibles of 20 workers were amputated 

 close to the base by the author. These bees appeared completely 

 normal, although they lived only 7 days on an average. When tested 

 with the oils of peppermint, thyme and wintcrgreen, honey and comb, 

 pollen, and leaves and stems of pennyroyal, they gave an average 

 reaction time of 4.8 seconds, while the average for the same odors 

 with unmutilated bees was 3.4 seconds. We may attribute this slight 

 difference in reaction time either to the injury caused by the amputa- 

 tion, or to the view that the mandibles help to perceive odors, or to 

 both. 



ANTENN.E AS SEAT OF OLFACTORY ORGANS 



(l) WITHOUT EXPERIMENTS 



Reaumur (1734) was the first to suggest that the olfactory organs 

 of insects lie in their antennas. 



Lesser (1745) says that the sense of smell of some insects is more 

 acute than that of man. He gives as two proofs of this, ( i ) that they 

 find their food with this sense, (2) that they scent food farther than 

 man does. He says that the antennae are " noses " and that they 

 enable their owners to smell odors near or far away. 



Baster (1770) remarks that no one doubts that insects can smell, 

 for flies, purely through olfaction, find their way to tainted meat. He 

 also states that water insects can smell. Baster states that no insects, 

 whether living in the air, under water, or in the earth, have the seat 

 of smell in the antenuc'e. 



