344 



N. E. McINDOO 



Fig. 24 Antennal organs of the honey bee copied from Schenk. A, an anten- 

 nal joint of a drone, showing a few of the many pore plates (PorPl) and a group 

 of Forel's fiasks (FFl), X 100; B, pore plates and Forel's flasks from a drone's 

 antenna, X 400; C, pore plates {PorPl), pegs (Pg), and tactile hairs (THr) from 

 a worker's antenna, X 400; D, internal anatomy of a pore plate and of a tactile 

 hair; E, the same of a peg, F, the same of a tactile hair; G, the same of a Forel's 

 flask; H, the internal anatomy of a pit peg. D — H, X 500. 



1 



If the reaction time of each caste is compared with the total 

 number of olfactory pores a consistent inverse ratio is obtained. 

 A drone has 2600 pores and responds in 2.9 seconds; a worker 

 possesses 2200 pores and responds in 3.4 seconds and a queen 

 has 1800 pores and responds in 4.9 seconds. 



Pore plates are not the olfactory apparatus in all insects, be- 

 cause they are entirely absent in the Lepidoptera. The pegs 



