114 A BOOK OF INSECTS 



beset with many hundreds of end-organs which, by a 

 system of nerves, are brought into close association with 

 the brain. The female has no such special sense endow- 

 ments. She may, indeed, exhibit signs of great simplifica- 

 tion, such as the complete absence of wings. But she is 

 provided with a scent-producing gland, from which a 

 peculiar perfume streams out upon the breeze, and is 

 carried over the countryside. This perfume is usually so 

 delicate as to be quite outside the range of human percep- 

 tion, yet it is detected at a great distance by the males, 

 which are guided by it to their mates. Conversely, the 

 males of some butterflies and moths — possibly of other 

 insects as well — possess scent glands on the legs and 

 wings, which are believed to render their owners more 

 charming to the opposite sex. On all counts, therefore, 

 we are justified in the belief that the perceptual world 

 of the insect — its inner realisation of material things — 

 is chiefly built up from impressions which are derived 

 through its sense of smell. 



The sense of touch, probably the oldest of all the 

 senses, is manifestly possessed by insects ; while in some 

 it appears to be highly developed. The antennae of blind 

 cave insects are exquisitely sensitive to tactile stimuli ; 

 while some of the most careful observers of ants and their 

 ways are agreed that these insects are able to communicate 

 with one another by a kind of touch-language. An ant 

 that chances upon a supply of food starts homeward, and 

 meets a fellow worker on the way. A mutual stroking 

 and patting of antennae follows, and then the tw r o ants go 

 back to the food in company. In a short time the news 

 is passed on to other members of the community, and 

 they in their turn hurry to the prize. 



The tactile end-organs of insects appear to take the 

 form of minute hairs or bristles, each in connection with 



