PACKAUD] r^SECTS OF THE PLANT HOUSE. 103 



It is not by the sense of hearing as in the mosquito, for these 

 lepidopterous damsels have not the gift of song. Tiiey are 

 silent as the Sphinx. It is not 1)}' the sense of touch, as they 

 wing their way from places miles distant. Unless it is by 

 the sense of smell, a modification it is true of the sense of 

 touch, we are unable to account for this trait of assembling. 

 That burying beetles perceive carrion at great distances 

 through the sense of smell is not a matter of doubt, and it is 

 not unreasonable to suppose that undulations of odoriferous 

 particles, moving like waves of sound and light, strike the 

 delicate branches and hairs of the male antennae, causing 

 them to vibrate in unison, and thus powerfully excite the 

 amatory nature of these ardent suitors. 



So much for the feelers of insects in general and those of 

 our Aphis (Fig. 72) in particular. Now as we are drawing 



Fig. 7.2. 



Aphis. 



the legs we ma}^ notice that there are six of them attached to 

 the sides of the middle region of the bod}', the "thorax." The 

 number is invariably six in all winged insects. The thorax 

 consists of three segments or rings, and to the side of each 

 ring a pair of legs is attached. Now the legs are tube-like, 

 jointed at intervals, ending in two short toe joints. In most 

 insects there are five such joints in the toe, and ten joints in 

 all. The last joint ends in a pair of long and slender claws. 

 The hind body, or "abdomen," is full and rounded, alder- 

 manic in its proportions, and provided with two tubes, which 



7 



