THE HYPOPHARYNX 71 



In all insects this organ whether forming a soft, tongue-like, 

 anterior portion or 'fold of the labium, and " continuous with the 

 lower wall of the pharynx," or a hard, piercing, awl-like appendage 

 (fleas and flies), or a long, slender, hairy or setose, trough-like struct- 

 ure like the " tongue " of the honey-bee has a definite location at 

 the end and on the upper side of the labiuni, and serves to receive 

 at its base the external opening of the salivary duct. 



The hypopharynx, as well shown in its lingua condition in Or- 

 thoptera, is continuous with and forms the anterior part or fold of 

 the base of the coalesced second maxillae. It does not seem to be 

 paired, or to represent a pair of appendages. 



Opinion regarding the homology of this unpaired piercing organ 

 is by no means settled, and while there is a general agreement as to 

 the nature of the paired mouth-parts, recent observers differ very 

 much as to the morphology of the organ in question. 



It is the langue or lingua of Savigny (1816), the ligula of Kirby 

 and Spence (1828), the langue ou languette (lancette m&diane du suqoir) 

 of Duges (1832), the lingua of Westwood (Class, ins., ii, p. 489, 1840), 

 " the impaired median piercing organ " (" the analogon of the epi- 

 pharynx of Diptera") of Karsten (1864), the "tongue" of Taschen- 

 berg(1880). 



The name hypopharynx was first proposed by Savigny in 1816, 

 who, after naming the membranous plate which has for its base the 

 upper side of the pharynx, the epipharynx, remarks : " Dans quelques 

 genres, notamment dans les Euceres, le bord inferieur de ce meme 

 pharynx donne naissance a un autre appendice plus solide que le 

 precedent, et qui s'emboite avec lui. Je donnerai a ce dernier le 

 nom de langue ou < hypopharynx. Voila done la bouche des Hyme- 

 nopteres composee de quatre organes impaires, sans y comprendre la 

 ganache ou le menton ; savoir, la levre superieure, 1'epipharynx, 

 1'hypopharynx, et la levre inferieure, et de deux organes paires, les 

 mandibules et les machoires." 



As stated by Dimmock : " The hypopharynx is usually present in 

 Diptera (according to Menzbier absent in Sargus), and contains a tube, 

 opening by a channel on its upper surface; this channel extends 

 back, more or less, from the tip, and is the outlet for the salivary 

 secretion. The tip of the hypopharynx may be naked and used as 

 a lance (Hsematopota, according to Menzbier), or may be hairy 

 (Musca). The upper side of the base of the hypopharynx is 

 continuous with the lower wall of the pharynx ; its under surface 

 may entirely coalesce with the labium (Culex, male), may join 

 the labium more or less, anterior to the mouth (Musca), or, if 



