! 

 394 FOOD OF INSECTS. 



insects, that they possess in fact two pairs of jaws, an 

 upper and an under pair, both placed horizontally, not 

 vertically, the former apparently in most cases for the 

 seizure and mastication of their prey ; the latter, when 

 hooked, for retaining and tearing, while the upper com- 

 minute it previously to its being swallowed a . 



To the remainder of the class of insects, a mighty host, 

 jaws would have been useless. Their refined liquid food 

 requires instruments of a different construction, and with 

 these they are profusely furnished. The innumerable 

 tribes of moths and butterflies eat nothing but the honey 

 secreted in the nectaries of flowers, which are frequently 

 situated at the bottom of a tube of great length. They 

 are accordingly provided with an organ exquisitely fitted 

 for its office a slender tubular tongue, more or less long, 

 sometimes not shorter than three inches, but spirally con- 

 voluted when at rest, like the main spring of a watch, 

 into a convenient compass. This tongue, which they 

 have the power of instantly unrolling, they dart into the 

 bottom of a flower, and, as through a siphon, draw up a 

 supply of the delicious nectar on which they feed. A 

 letter would scarcely suffice for describing fully the ad- 

 mirable structure of this organ. I must content myself 

 therefore with here briefly observing that it is of a carti- 

 laginous substance, and apparently composed of a series 

 of innumerable rings, which, to be capable of such rapid 

 convolution, must be moved by an equal number of di- 

 stinct muscles ; and that, though seemingly simple, it is in 

 fact composed of three distinct tubes, the two lateral ones 

 cylindrical and entire, intended, as Reaumur thinks, for 

 the reception of air ; and the intermediate one, through 

 a PLATE VI. FIG. 4, 5. 10, 11. 24-26. 



