82 OF THE SENSES OF 



" Nostrils have not yet been recognized in insects ; 

 nor do we know in what part of the body they, or 

 any other organs corresponding to them, are placed. 

 Probably odours reach the sensorium through the 

 medium of a mechanism similar to our own, that is, 

 the air is introduced into some opening at the termi- 

 nation of the olfactory nerves ; and hence we should 

 examine if the stigmata* do not perform this function, 

 or whether the organ we are in quest of be not 

 situated in the head, or in some other part of the 

 body. With the view of elucidating the matter, we 

 made the following experiments : 



" 1. A pencil dipped in oil of turpentine one of 

 the substances most disliked by insects was pre- 

 sented successively to all parts of the body of a bee, 

 which did not appear in the least affected, whether 

 on approaching the thorax, abdomen, or stigmata of 

 the thorax. 2. We then took a fine pencil, that it 

 might reach every point of the head, and brought it 

 near the antennae, the eyes, and protruded trunk of a 

 bee in the act of feeding, but without producing the 

 least effect. It was otherwise on carrying it near the 

 cavity of the mouth, above the insertion of the pro- 

 boscis. At that instant the bee receded, left the 

 honey, and, beating its wings, while moving about in 

 much agitation, it would have taken flight had not 

 the pencil been withdrawn. Having renewed its 

 repast, we resumed the application, always carrying 



* Certain apertures, generally called stigmata, appear on 

 each side of the body of insects, which naturalists believe to 

 be appropriated exclusively to respiration. 



