THE HYPOPHARYNX 



73 



mtf.p 



FIG. 71. Section through the 

 anterior part of the head of Ana- 

 brus (the mandibles removed), 

 showing the relations of the hypo- 

 pharynx (hyp) to the opening of 

 the salivary duct (sd) : ff, galea ; 

 I, lacinia; mt, mentum ; oe, oesopha- 

 gus ; Ibr, labrum ; cl, clypeus. 



base of the tongue is narrow, and extends back to near the pharynx, 

 there being on the floor of the month, behind the tongue, two oblique, 

 slight ridges, covered with stiff, golden-yellow hairs, like those on 

 the tongue. The opening of the salivary duct is situated on the 

 \inder or hinder side of the hypopharynx, 

 between it and the base of the labium, the 

 base of the former being cleft ; the hollow 

 thus formed is situated over the opening, 

 and forms the -salivary receptacle. 



In the Locustidse (Anabrus, Fig. 71) the 

 tongue (hypopharynx) is a broad, some- 

 what flattened lobe arising from the upper 

 part of the base of the mentum and behind 

 the palpifer. This lobe is cavernous un- 

 derneath, the hollow being the salivary 

 receptacle (sr) ; the latter is situated over 

 the opening of the salivary duct, which is 

 placed between the base of both the hypo- 

 pharynx and the labium. The salivary 

 fluid apparently has to pass up and around on each side of the hypo- 

 pharynx in order to mix with the food. 



These relations in the Orthoptera are also the same in the 

 Perlidse, where the hypopharynx is well developed, forming an 

 unusually large tongue-like mass, nearly filling the buccal cavity. 



In the Odonata the lingua is a small, rounded lobe, as also in the 

 Ephemeridse ; in the nymph, however, of Heptagenia (Fig. 72) it is 



highly developed, according 

 to Vayssiere, who seems in- 

 clined to regard it as repre- 

 senting a pair of appendages. 

 The tongue in Hemiptera is 

 said by Leon to be present in 

 Benacus griseus (Say) and to 

 correspond to the subgalea of 

 Brulle or hypodactyle of Au- 

 douin (Fig. 73), but this ap- 

 pears to correspond to the labium proper, rather than a true lingua, 

 the latter not being differentiated in this order. In the Coleoptera 

 the lingua is rather small. In beetles, as Anopthalmus (Fig. 74), it 

 forms a setose lobe ; and a well-developed nerve, the lingual nerve, 

 passes to it, dividing at the end into several branches (n-l). In Sialis 

 the lingua is short, much less developed than usual, being rounded, 



Fio. 72. Lingua of a May-fly, Ifeptitffenia longi- 

 t'ltmlti. x!6: )., central; /,, lateral pieces. After 

 Vayssiere from Sharp. 



