Chap. IV. 



TANAIS DUBIUS. 



21 



filaments, wliich stand in groups of from five to seven 



together. 



Figs. 3-6. 1 



* Fig. 3. Head of the ordinary form of the male of Tanais duhius (?) 

 Kr. magn. 90 times. The terminal setse of the second pair of antennas 

 project between the cheliferous feet. Fig. 4. Buccal region of the same 

 from below ; A, labrum. Fig. 5. Head of the rarer form of the male, 

 magn. 25 times. Fig. 6. Flagellum of the same, with olfactory fila- 

 ments, magn. 90 times. 



