A STUDY OF INSECT MOUTHPARTS 9 



pharynx. Removing the labrum the pair of heavy black oppos- 

 able jaws, or mandibles, is exposed. These are biting structures 

 par excellence. They are toothed and movable laterally, in- 

 stead of vertically as in the vertebrates. Dislodging the man- 

 dibles brings the pair of maxilla, or accessory jaws, into view. 

 These organs are also called^/ maxilla. These are composite 

 structures, each separable into lacinia, galea, palpus, cardo and 

 stipes, which should be carefully noted, inasmuch as they undergo 

 great modification in the remaining types of mouthparts. The 

 two supporting sclerites are called the cardo (basal), and stipes 

 (the second) while the distal lobes are called, i, the maxillary 

 palpus (a jointed structure), 2, the galea (median and fleshy), 

 3, the lacinia (inner and toothed, capable of aiding in comminut- 

 ing food). 



Underneath the maxillae and forming the floor of the mouth, 

 lies the lower lip, or labium, a double structure, frequently called 

 the second maxilla. On the same plan as the maxillae, the 

 labium consists of a basal sclerite, the submentum, followed by 

 the mentum, upon which rest the labial palpi (a pair of outer, 

 jointed structures, to the right and left) and the lignite (a pair 

 of straplike pieces which together correspond to the upper lip). 

 The labium is, like the maxillae, also subject to much modifica- 

 tion. 



The fleshy organ still remaining in the mouth cavity after the 

 parts just described have been removed, is the tongue, or hypo- 

 pharynx, functionally comparable to the tongue of vertebrates, 

 an organ of taste. 



Draw side and front view of grasshopper's head; also make a 

 drawing of each mouthpart separately, labelling all parts. 



B. Hymenopteron type. 



In this type the two general classes of mouth structures, the 

 Mandibulate and Haustellate, find a rather strong development 

 in the same species, though the former structures are not con- 

 cerned as comminuting organs with respect to food. The honey- 



