THE HYPOPHARYNX 



75 



Neuroptera, and the hypopharynx of the bees (Fig. 86). Lucas 

 describes and figures it under the name of " haustellum," but does 

 A B 



not homologize it with the hypopharynx. The caddis-flies have been 

 observed to drink water and take in both fluid and fine particles 



of solid food, and to use the haustellum 

 for this purpose, the end being pro- 

 vided with minute sense-organs like 

 those on the first maxillary lacinia, and 

 possibly of a gustatory nature. 



The spinneret of the larvae of Lepi- 

 doptera is evidently the homologue of 

 the hypopharynx of insects of other 

 orders. It will be seen that the liomol- 

 ogy of the different parts is identical, 

 the common duct of the silk-glands 

 opening at the end of the hypo- 

 pharynx, which here forms a complete 

 tube or proboscis extending beyond the 

 end of the labium, in adaptation to its 

 use as a spinning organ. 



Walter refers to Burgess's discovery 

 of a hypopharynx in Danais archippus, 



FIG. 76. Hypopharynx of Erio- 

 cephala calthella : lig, ligula, its mem- 

 branous hinder edge ; lig', anterior 

 horny edge of the ligula-tube opening 1 

 outwards ; hp, contour of the hypo- 

 pharynx ; mi, mala interior (lacinia) ; 

 me, mala exterior (galea), of second 

 maxilla; mas'p, labial palpus. After 

 Walter. 



