NO. 14 SENSE ORGANS ON MOUTH-PARTS OF BEE McINDOO 



29 



that the sense cells begin to differentiate when the hypodermal cells 

 begin to form the chitin. It is thus seen that by the time the chitin is 

 of considerable thickness, the sense fibers have united with the pore 

 apertures and the formation of the cones has begun. There are two 

 possible functions of the cones : (1) to strengthen the chitin forming 

 the bottoms of the flask-shaped pores, and (2) to insure firm attach- 

 ments for the peripheral ends of the sense fibers. The latter function 



Fig. 5. — Internal anatomy and superficial appearance of olfactory pores on 

 mouth-parts, head and cervical plate of worker. honey bees, x 580. A to F, 

 cross-sections ; A, one of largest olfactory pores from mandible of a 20-day-old 

 pupa, showing sense cell (SC), pore aperture (PorAp), and hypodermal 

 secretion (HypS) forming the cone (Con) ; B, two olfactory pores and one 

 sense cell from base of glossa ; C, three olfactory pores and one sense cell from 

 maxilla; D, a group of olfactory pores and sense cells in labial palpus ; E, an 

 olfactory pore from side of head ; F, two olfactory pores from buccal cavity ; 

 G to K, superficial appearances : G, three of largest olfactory pores on man- 

 dible ; H, one of the two groups of olfactory pores on base of tongue ; I, group 

 of olfactory pores on maxilla ; J, group of olfactory pores on labial palpus ; K, 

 three of largest olfactory pores on cervical plate. These pores may be located 

 by referring to figures 7, 8, 9 C and 10. See page 54 for explanation of 

 abbreviations. 



