sequence of the transparency of the chitin ; (/) 

 circular chitinous plates with radiating ridges 

 on the underside of the abdomen ; (g) sloping 

 plate which serves to turn the hair, which is 

 held, away from the anus. On the left side 

 of the figure the retractor muscles of the lips 

 are indicated. 



Figs. 2 to 4 are copied from the author's drawings 

 in the ' Journal of the Linnean Society ;' figs. 5 to 11 

 from the author's drawings in the ' Journal of the 

 Royal Microscopical Society,' by permission of those 

 Societies. 



