TEXT-BOOK OF ENTOMOLOGY 



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cither mandibles or maxillaa are present, its base may join them 



(Culex, female)." (p. 43.) 



We will now briefly describe the lingua, first of the mandibnlate 



or biting insects, and then its specialized form, the hypopharynx of 



the haustellate and lapping insects. 



The lingua (hypopharynx) exists in 

 perhaps its most generalized condition 

 in the Thysanura (Fig. 69), where it 

 forms a soft projection, having the same 

 relations as in Anabrns and other Or- 

 thoptera. 1 



In the cockroach (Fig. 70), as stated 

 by Miall and Denny, the lingua is a 

 chitinous fold of the oral integument 

 situated in front of the labiuni, and ly- 

 ing in the cavity of the mouth. The 

 common duct of the salivary glands 



Ibr 



rnx. 



Fir,, ra.- section of head of Ma- enters the lingua, and opens on its 



chili* iiKii-itiiint : In/p, hypopharynx; hinder snrflPP Thp lincmn iqqnrmnrtprl 

 I1>,-, labnnn; t, tentorium ; ph, room Liace. .ngua IS SUppOUl 



in which the mandibles move on each l-, v a phitinnnc cVplpfrm fTTio-o 70 R Q9 



other ; /,, para-lossa ; m;r , labium D J c * 1 S S - ( U > - > <^5 



./, salivary duct; x.ffl, salivary pland. o/irA Thp thin fhitinnnq Qiirfqpp nf thp 



oe, uesophagus. - After Oudeuians. ^ * ' 



lingua is hairy, like other parts of the 



month, and stiffened by special chitinous rods or bands." (Miall 

 and Denny.) 



In the Acrydiidse (Melanoplus femur-rubrum) the tongue is a large, 



c 



B 



O 



FIG. 70. Hypopharynx of Periplaneta orien- 

 tufix; the arrow points out of the opening of tin- 

 salivary duct: A, origin of salivary duct. B, side 

 view. V, front view. After Miall and Denny. 



membranous, partly hollow 



expansion of the base of the 



labium. It may be exposed 



by depressing the end of the 



labium, when the opening of 



the salivary duct may be seen 



at the bottom or end of the 



space or gap between the 



hinder base of the tongue, 



and the inner anterior base of 



the labium, as shown by the 



arrows in Fig. 70. It is somewhat pyriform, slightly keeled above, 



and bearing fine stiff bristles, which, as they point more or less 



inwards, probably aid in retaining the food within the mouth. The 



1 Uzel states that what is regarderl as the ligula of Campodea is formed from the 

 strniite of the first maxillary segment ; while t ho two parts regarded as paraglossaj 

 grow out from the. slcrnite of the mandihular segment, and these three structures 

 together he regards as the hypopharynx. (/ool. Auzeiger, July 5, 1897, p. 234.) 



