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 



FIG. 144. Promethea moth, male, showing specialized antennae. 



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 antennae (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 



