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 maxillae), 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 
