282 



TEXT-BOOK OF ENTOMOLOGY 



necessarily must come in contact with the food as it enters the 

 mouth and passes down the throat. 



Kraepelin (1883) discovered taste-organs on the proboscis of the 

 fly, and taste-hairs at the end of the tongue of the hunible-bee 

 (Fig. 285), and afterwards Lubbock critically discussed the subject, 



ff H 



#^4' 



<tohX;-', 







Fio. 284. Taste-pits on the epipharynx (C) of the honey- 

 bee : B, horn/ ridge ; K, It, taste-pits ; L, A, A, muscular fibres ; 

 S, <S", a b c d ef, section of skin of oesophagus. After Wolff. 



&"* 



Fm. 285. Tip of the pro- 

 boscis of the honey-bee, x 140 : 

 Z, terminal button or ladle ; (fx, 

 taste-hairs; *S7(, guard-hairs; 

 lib, hooked hairs. After Will. 



and concluded that the organs of taste in insects are situated " either 

 in the mouth itself, or on the organs immediately surrounding it." 



Structure of the taste-organs. - - The organs have been best studied 

 by Will, who, besides describing and figuring the chitinous struct- 

 ures, such as the pits or cups, hairs and the pegs, showed that they 

 were the terminations of ganglionated nerves. 



Figure 286 represents the taste-cups on the maxilla of a wasp, and 

 Fig. 287 the taste-cone or peg projecting from the cup or pit. The 

 cell out of which the pit and projecting hair or peg are formed is a 

 modified hypodermis cell ; and the seta is apparently a modification 

 of a tactile hair, situated at the end of a nerve, which just beneath 

 the chitinous structures passes into a ganglion-cell, which sends off a 

 nerve-fibre to the main nerve. 



Will detected on the tongue of the yellow ant (Lasiusjfavits) from 

 20 to 24, and in Atta from 40 to 52, of these structures. The num- 

 ber of pits on the maxilla? vary much, not always being the same on 

 the two sides of the same insect. We have observed these taste- 

 cups in the honey and humble bee, not only at the base of the second 

 maxillae (Fig. 288, </), but also on the paraglossse (pg). 



Distribution in other orders of insects. The writer has detected these 

 taste-cups in other orders than Diptera and Hymcnoptera. They very gener- 

 ally occur in niandibulate insects on the more exposed surface of the epipharynx 



