OLFACTORY ORGANS OF INSECTS. 203 



The perception of Insects with regard to odours is farther 

 evidenced by the peculiar scents which several of them are 

 known to emit, and the purposes to which their emission is in 

 some instances applied. In the case, for example, of the Ant, 

 so well known to be redolent of Formic acid, the perfume left as 

 it travels on its line of march, has been ascertained to serve 

 as a guiding clue to its comrades in the rear. 



Though thus generally admitted to be what the Italians 

 would call most excellent Nasuti, Insects still puzzle us as to 

 what exact part of their enigmatical frames may be con- 

 sidered an olfactory organ. This is a point on which natu- 

 ralists of the highest credit have been so much at issue, that 

 when we read the opinions of each, and the experimental 

 evidence adduced by each in support of his own, we seem as if 

 we could scarcely arrive, between them, at any nearer conclusion 

 than that Insects must be all nose. 



By Kirby and Spence, they are invested indeed with the nasal 

 appendage corresponding in position, if not always in shape, 

 with the conspicuous proboscis of a man, a monkey, and the 

 other Mammalia. Huber also opined that their organ of smell 

 is seated in the head and near the mouth, at all events in the 

 case of the Bee ; and in proof of his position, he tells us, that 

 having dipped a fine pencil in oil of turpentine, he approached 

 it carefully to every part of a Bee's head, but without causing 

 the least apparent sensation until approximated to that in 

 question, when the Insect starting suddenly from the honey 



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