56 Organs of Smell in Insects. 
antenna. The function of the antennz is now pretty weli 
if not wholly understood. That they often serve as most 
delicate touch-organs no observing apiarist can doubt. 
Tactile nerve-ending hairs are often found in great num- 
bers. With the higher insects, like most Hymenopterons, 
this tactile sense of the antenne is doubtless very import- 
ant, 
It is now fully demonstrated that the sense of smell is 
located in the antenna. Sulzer in the last century sug- 
gested that an unknown sense might exist in the antenne. 
Reaumur, Lyonet, Bonnet, etc., thought this might be the 
sense of smell. Dumeril, Lehrman, who said that a 
nerve vessel and muscle entered the antennz, and Cuvier, 
etc., thought the sense of smell was located in the spiracles 
or breathing mouths. Huber thought the organ of smell 
was located in the mouth. Latreille and Newport, of this 
century, believed the antennz contained the organs of 
hearing. Strauss-Durkheim located them in the spiracles. 
While Wolff wrote a beautiful monagraph to prove that 
the sense of smell was situated in the hypo-pharynx beneath 
the labrum. Erichson in 1848 discovered pits in the 
antenna—pori—covered with a membrane (Fig. 11, 4) 
which he thought organs of smell. The next year Bur- 
meister found hairs in these pits in beetles, which varied 
according as the beetle ate plant-food or carrion. 
Leydig in 1855 showed that Erichson was correct, that 
there were pits also on the antenne and pegs (Fig. 11, p) 
or tooth-like hairs, perforated at the end—olfactory teeth. 
It remained for Hauser (1880) to complete the demonstra- 
tion. He experimented with insects by the use of carbolic 
acid, turpentine, etc. He found that this greatly disturbed 
the insects when their attennz were intact, and that even 
after he had withdrawn the offensive substance the insect 
would continue to rub its antenna as if to remove the dis- 
turbing odor. A sort of holding its nose. He then cut 
off the antenne to find that the insect was now insensible 
to the irritant. He next put food before the insects, which 
was quickly found and appropriated; but after the antennz 
were cut off the food was found with difficulty if at all. 
Experiment showed that jn mating the same was true. 
