ANATOMY AND PHYSIOLOGY 



LABIUM = MAXILLA 



palpus = palpus 

 paraglossa = galea 

 . glossa = lacinia 

 palpiger = palpifer 

 mentum = stipites 

 submentum with gula = cardines 



In most mandibulate orders the glossae unite to form a single me- 

 dian organ, as in Harpalus (Fig. 47, g). The 

 labium forms the floor of the pharynx and 

 assists in carrying food to the mandibles and 

 maxillae. 



The use of the term " second maxillae" for the 

 labium of an insect is open to objection, as it im- 

 plies an equivalence with the second maxillae of 

 Crustacea which is by no means established. 



The tongue, or hypopharynx, is a median 

 fleshy organ (Fig. 44) which is usually united 

 more or less with the base of the labium. In 



insects in general, the salivary glands open at 



, i -, r , , , , T .-, FIG. 47. Labium of Har- 



the base of the hypopharynx. In the most gen- pdus ca u g i nosus , ventral 



eralized insects, Thysanura and Collembola, the as P ect ; , * united g lossae 



termed the glossa; m, men- 

 hypopharynx is a compound organ, consisting of turn; p, palpus; & palpiger; 



a median ventral lobe, or lingua, and two dorso- ^ST*! J3L ^ 

 lateral lobes, termed superlinguce by the author, tion of the labium beyond 



,. . r ... , , the mentum is termed the 



Superhnguae occur in a few other mandibulate u g ui a . 

 orders (Orthoptera, Fig. 48; Ephemerida, Fig. 



49), but have not yet been recognized in the more 

 specialized orders of insects. 



Suctorial Types. Owing to their greater com- 

 plexity, suctorial mouth parts are not nearly so well 

 understood as the mandibulate organs, but enough 

 has been learned to enable us to homologize the two 

 types, even though morphologists still disagree in 

 regard to minor details of interpretation. 



The suctorial, or haustellate, orders are Collem- 

 bola (in part), Thysanoptera (in part), Hemiptera, 

 Trichoptera (imperfectly), Lepidoptera, Diptera, 

 Siphonaptera and Hymenoptera (which have func- 

 tional mandibles, however). 



FIG. 48. Hypo- 

 pharynx of Hemimerus 

 talpoides. I, lingua; s, 

 superlingua. After 

 HANSEN. 



