THE MOUTH. 43 



presents the mouths of sucking insects as " totally 

 useless;" and thence concludes, " they can do no in- 

 jury to agriculture/' a conclusion as false as the former 

 is impious. 



I have stated this in order to prevent misconcep- 

 tion, which, from the imperfection of terms, is but too 

 apt to mislead a genuine field observer, and is cer- 

 tain to mystify and bewilder a compiler or a cabinet 

 naturalist. 



Comparing the jaws of an insect with those of 

 man, or with the bill of a bird, we find that while the 

 motion of the latter is upwards and downwards, the 

 motion of the former is forward from the sides, Ac- 

 cording to M. Audouin, who follows M. Savigny, the 

 mouth of an insect consists of the upper lip, a pair 

 of upper jaws, a pah- of under jaws, and an under lip. 



1. The upper lip ( J ) is a flat, usually horny, plate, 

 joined horizontally to the lower part of the face, and 

 closing the mouth. 



2. The upper jaws (*), one on the right and another 

 on the left, resemble, in eating insects, a large horny 

 tooth, more or less curved, often indented, andjointea 

 into the sides of the head immediately below the upper 

 lip, being moveable, and without any pieces attached 

 to them, as is the case with the under jaws. In some 

 moths the upper jaws are exceedingly small, with a 

 part as if scooped out in each. 



3. The under jaws ( 3 ) are also two in number, and are 

 jointed into the right and left of the inner cavity of the 

 mouth, immediately below the upper jaws ; they re- 

 semble the upper jaws in moving from the sides for- 

 ward ; but are seldom so strong, being rather mem- 

 branous than horny, particularly at the tips ; they also 

 differ in being jointed, while the upper jaws are 

 solid. 



(1) In Latin, Labrum. (2) In Latin, Mandibute. 



(3) In Latin, Maxillae. 



