44 MEMBERS OF INSECTS. 



Usually, at the place where the horny texture ends, 

 and the membranous begins, there is, on each of 

 the under jaws, a remarkable little member, in 

 form of a thread, composed of from four to six joints, 

 commonly tipt with a part less homy than the rest, 

 jointed upon a stem or footstalk that supports it, and 

 furnished with hairs. These jointed members are 

 called feelers (*), though the term is objectionable, 

 because their use is not well ascertained. 



Sometimes the inner front of the lower jaw forms a 

 sort of acute lobe, or even a large scale, furnished at 

 the tip with a hook, and resembling the upper jaws. 

 In that case, the outer division of the upper jaw takes 

 sometimes the form of a case orarched shield ( 2 ) ; some- 

 times it constitutes a second feeler which is short, and 

 inserted within it. These are called inner feelers ( 3 ), to 

 distinguish them from the outer, and longer feelers( 4 ), 

 described above. 



The only organs in other animals similar to these 

 feelers are the whiskers in the cat, the mouse, the seal, 

 the night-jar, and other birds which feed on insects ; 

 and the beardlets in the cod, the barbel, and other 

 fish. 



4. The under lip ( 5 ), which closes the mouth below, 

 is not unlike a second pair of upper jaws united, on 

 their inner side, and covered in the greater part by a 

 horny projection called the chin ( 6 ). 

 Each of the halves of the under lip carries a feeler 

 smaller than those of the under jaws, and composed 

 of four or more joints. The projection beyond the 

 chin is called the tonguelet ( 7 ). In many insects there 

 is found a small piece ( 8 ) on each side, arising in the 



(1) In Latin, Palpi. (2) In Latin, Galea. 



(3) In Latin, Palpi interni. (4) In Latin, Palpi extern*. 

 . (5) In Latin, Labium. (6) In Latin, Mentum. 



(7) In Latin, Lingula. (8) In Latin, Paraglossa. 



