THE SENSES OF INSECTS — MelNDOO. 



477 



the antennae (feelers) and jaws are probably the most sensitive, 

 although the tongue and other mouth parts are also extremely sensi- 

 tive, as may be judged from the tactile hairs shown in figure 9. The 

 other appendages are likewise well provided with touch hairs and in 

 fact every prominence on them which is apt to come in contact with 

 objects bears a group 

 of these hairs, which 

 are usually much 

 larger than those 

 found on the anten- 

 nae and mouth parts. 

 Even the palate and 

 pharynx are pro- 

 vided with many del- 

 icate touch hairs; 

 and the head and 

 body of insects also 

 bear many irregu- 

 larly scattered sense 

 hairs, although the 

 majority of the hairs 

 found on insects are 

 not connected with 

 nerves. 



In size the tactile 

 hairs vary from very 

 large ones (fig. 9, 

 c 13 ), widely distrib- 

 uted, to microscopic 

 ones found in the 

 mouth cavity and 

 elsewhere. In struc- 

 ture they also vary 

 considerably, but 

 may be roughly di- 

 vided into spinelike 

 (figs. 10, 12, and 13) 

 and peglike hairs 

 (fig. 11), the former usually being the larger and more common, 

 while the latter are always microscopic and found only on the an- 

 tennae and on some of the mouth parts. The peglike ones shown in 

 figure 11 are called olfactory hairs by other authors; they are found 

 only on the antennae of insects, excepting the antennae of drone 

 honeybees. The spinelike ones shown in figure 12 are found only on 

 the epipharynx or palate; these, and also those on the tongue (fig. 9, 



Figs. 9 to 13. — Organs of touch on the honeybee. Fig. 9, 

 diagram of mouth parts of a worker, spread out flat, 

 showing location and number of touch hairs (6, c, e, 

 and f), all of which are connected with nerves, while the 

 long hairs on the tongue (Gls) are not connnected with 

 nerves. The latter hairs are omitted in the drawing. 

 Figs. 10 to 13, sections of touch hairs, showing nerves 

 (V) running into bases of hairs; enlarged 500 times. 



