Packard.] INSECTS OF THE PLANT HOUSE. 
103 
It is not by tho sense of hearing as in the mosquito, for these 
lepidopterous damsels have not the gift of song. They are 
silent as the Sphinx. It is not by 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. 72. 
the legs we may notice that there are six of them attached to 
the sides of the middle region of the body, 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 
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