58 
COMPARATIVE ZOOLOGY. 
Fig. 21.—Mouth of a Locust dissected: 1, labrum, or upper lip; 2, mandibles; 3, 
jaws; 4, labium, or lower lip; 5, tongue. The appendages to the maxillae and 
lower lip are palpi. 
the suctorial (as the Butterfly). In the former group, the 
oral apparatus consists of two pairs of horny jaws (mandi¬ 
bles and maxillce ), which work horizontally between an 
upper ( labrum ) and an under (labium) lip. The maxillae 
and under lip carry sensitive jointed feelers (palpi). The 
front edge of the labium is commonly known as the tongue 
( ligula ). 21 In such a mouth, the mandibles are the most 
important parts; but in passing to the suctorial Insects, 
we find that the mandibles are secondary to the maxillae 
and labium, which are the only means of taking food. In 
