ANATOMY OF INSECTS EXTERNAL 



termed the second maxillce. The labium forms the floor of the 

 mouth and assists the mandibles and maxillae with the food. It is 

 hinged to the head at its base (by the mentum), and projecting 

 from either side is a palpus , similar in form and function to the 

 maxillary palpi. Between the palpi are one or two pairs of lobes, 

 the ligula. 



Projecting into the cavity of the mouth from the inner sur- 

 face of the labium is the hypopharynx, or tongue. This in the 



I6r 



FIG. 1 5. Mouth-parts of the squash-bug 



lab, labium, forming a sheath for the other parts ; 

 Ibr, labrum, fitting into the lower part of the 

 suture of the labium ; md, mandible ; mx, max- 

 illa. Mandibles and maxillae pulled out of labium 



FIG. 1 6. Side view of head 



of butterfly, with part 



of antennae (a) removed, 



showing mouth-parts 



mx, maxillae ; /, labial palpus 



grasshopper is a fleshy, tonguelike organ, but in some orders it 

 is quite differently developed. The salivary glands open near its 

 attachment. 



Suctorial type of mouth-parts. The mandibulate mouth-parts 

 of the different orders are all of so similar a type as to be appar- 

 ently homologous. The suctorial mouth-parts consist of several 



