46 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 63 



In size the olfactory pores vary much. Those of an ant vary more 

 in size than do those of the hornet or honey bee. The pores on the 

 wings are always much smaller than are those on the legs and they 

 vary less in size. In proportion to the sizes of an ant and of a worker 

 honey bee, the pores of the ant are much larger. 



Under the microscope with transmitted light the olfactory pores 

 appear as bright spots. At the first glance they resemble hair sockets 

 (fig. 5, PorApHr) from which the hairs have been pulled, but after 



Por3 



PorW-' 



Fig. 5. — Group 6 of the olfactory pores from the hind leg of a worker bee, 

 showing the external appearance, x 700. 



a closer examination a striking ditTerence is usually seen. Each 

 bright spot is surrounded by a dark line, the pore wall (figs. 5 and 6, 

 PorW). Outside this line the chitin (fig. 5, PorB) may be light or 

 dark in color, but inside the line the chitin (figs. 5 and 6, ChL) is 

 almost transparent, and at the center there is an opening, the pore 

 aperture (figs. 5 and 6, PorAp). 



The olfactory pores consist of inverted flasks in the chitin and of 

 spindlelike sense cells lying beneath the mouths of the flasks (fig. 6). 

 About two-thirds of the space at the bottom of the flask is occupied 

 by a hollow chitinous cone (fig. 6, Con) which is not separated from 



