ANATOMY AND PHYSIOLOGY 



LABIUM = MAXILLA 



palpus = palpus 

 paraglossa = galea 



glossa = lacinia 

 palpiger = palpifer 

 tncntum sti piles 

 submcntum with gula = cardines 



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

 dian organ, as in Ear pains (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 hypo pharynx, 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 



, , . FIG. 47. Labium of Har- 



the base of the hypopharynx. In the most gen- pa i us ca i; g i n osus, ventral 



' eralized insects, Thysanura and Collembola, the as P ect ; s, united glossae, 



J termed the glossa; m, men- 



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



a median ventral lobe, or lingua, and two dorso- ^ n tJ^ agl T?e median pot 

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



... , the mentum is termed the 



Superlmguas 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 Hcmimcrus 

 talpoides. I, lingua; s, 

 superlingua. After 

 HANSEN. 



