THE SPECIAL SENSES 231 
own community. In the insectary at Cornell University, 
a few years ago, a few females of the beautiful promethea 
moth (Callosamia promethea) were inclosed in a box, 
which was kept inside the insectary building. No males 
had been seen about the insectary nor in its immediate 
vicinity, although they had been sought for by collectors. 
A few hours after the beginning of the captivity of the 
female moths there were forty male prometheas fluttering 
about over the glass roof of the insectary. They could not 
Fie. 144.—Promethea moth, male, showing specialized antennzx. 
see the females, and yet had discovered their presence in 
the building. The discovery was undoubtedly made by the 
sense of smell. These moths have very elaborately devel- 
oped antenne (Fig. 144), finely branched or feathered, 
affording opportunity for the existence of very many smell- 
ing-pits. 
The keenness of scent of hounds and bird dogs is famil- 
iar to all, although ever a fresh source of astonishment as 
we watch these animals when hunting. We recently 
watched a retriever dog select unerringly, by the sense of 
smell, any particular duck out of a pile of a hundred. In 
