70 



TEXT-BOOK OF ENTOMOLOGY 



FIG. 77. Labiiim of Mioropteryas ander- 

 schella seen from within (the labial palpi (mx.'p) 

 removed to their basal joint). Lettering as in 

 Fig. 76. After Walter. 



remarking that this organ in the achilt Eriocephalidae (Tig. 76) 



exhibits a great similarity to the relations observable in the lower 



insects, adding : 



" The furrow is here within coalesced with the inner side of the 



labium, and though I see in the entire structure of the head the 



inner edge of the ligula tube 

 extended under the epipharynx 

 as far as the mandible, I must 

 also accept the fact that here 

 also the hypopharyiix extends to 

 the mouth-opening as in all other 

 Slicking insects with a well- 

 developed underlip, viz. the Dip- 

 tera and Hymenoptera." 



He has also discovered in 

 Micropteryx a paired structure 

 which he regards as the hypo- 

 pha.rynx (Fig. 77). As he states: 

 "A portion of the inner sur- 

 face of the tube-like ligula is 



covered by a furrow-like band which, close to the inner side, is 



coalesced with it, and in position, shape, as well as its appendages 



or teeth on the edge, may be 



regarded as nothing else than 



the hypopharynx." 



A hypopharynx is also pres- 

 ent in the highest Lepidoptera, 



Burgess having detected it in 



Danuis archippus. He states 



that the hypopharynx forms 



the floor of the pharyngeal 



cavity ; " it is convex on each 



side of a median furrow (Fig. 



78, kpll) and Somewhat reseill- 



1 1 cs in shape the human breast. 



The convex areas are dotted over with little papilla, which possibly 



may be taste-organs." 



As a piercing organ the hypopharynx reaches its greatest develop- 

 ment in the Siphonaptera and Diptera, where the chitinous parts are 

 greatly hypertrophied, the fleshy tongue-like portion so developed in 

 the mandibulate orders being greatly reduced. The chitinous parts are 

 alike on each side of the median organ, being bilaterally symmetrical. 



FIG. 78. Hypopharynx (hpfi^i of Panais : cl, 

 xi/, salivary durt : m, labial palp muscles ; 

 frontal muscle; j>h, pharynx; cor, cornea. 

 After Burgess. 



