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 arid 

 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 



