A TRUFFLE-HUNTER 237 



to us. It is also known to the insect. It is this that 

 warns the Saprinidae of the fetid arum, the Silphidae and 

 the Necrophori of the putrid mole. 



The second category of odour, far superior in its 

 action through space, escapes us completely, because 

 we lack the essential sensory equipment. The Great 

 Peacock moth and the Oak Eggar know it at the time 

 of their nuptial festivities. Many others must share it in 

 differing degrees, according to the exigencies of their 

 way of life. 



Like light, odour has its X-rays. Let science, instructed 

 by the insect, one day give us a radiograph sensitive to 

 odours, and this artificial nose will open a new world 

 of marvels. 



