76 



TEXT-BOOK OF ENTOMOLOGY 



Labium of Mioropttrwe 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 adult Eriocephalidse (Fig. 76) 

 exhibits a great similarity to the relations observable in the lo\ver 

 insects, adding : 



" The furrow is here within c6alesced 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 

 sucking 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- 



FIG. T7.-Labiuin of Micropteryx ander- pharynx (Fig. 77). As lie 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 hypopharyiix." 



A hypopharynx is also pres- 

 ent in the highest Lepidoptera, 

 Burgess having detected it in 

 Danais 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, hph) and somewhat resem- 

 bles in shape the human breast. After B ur e ess - 



The convex areas are dotted over with little papillae, 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. 



FlG 78 ._ Hy popharvnx 



of nanais: </. 



