APPENDIX TO CHAPTER V 79 



Anus in ultimate segment; body without 



bunches of hairs. 

 Ci. Mandibles not rudimentary ; mouth 



parts not suctorial. 

 d\. Segments 30 or more. 



e\. Anal segment produced into 



a spine .... Julidce 



(Ex. Julus) 



62- Anal segments produced into 

 2 slender papillae, or uni- 

 dentate .... Craspedosomidm 

 d z . Segments 19 or 20 . . . Polydesmidce 



(Ex. Polydesmus) 

 C2. Mandibles rudimentary, mouth parts 



reduced .- Polyzoniidce 



KEY TO COMMONER SPECIES OF THE GENUS LITHOBIUS 



ai. Posterior angles of none of dorsal plates pro- 

 duced ; pores on coxae uniseriate. 

 b\. A nal feet armed with 1 spine ; posterior coxae 

 unarmed ; spines of first pair of feet, 2, 2, 

 2-2, 3, 2 (Central States) . . . bilabiatus 



6 2 . Anal feet armed with 3 spines ; coxae with 

 indistinct spine ; spines of first pair feet, 

 2, 3, 2 (Central States) . . . ' _.: cardinalis 



2 - Posterior angle of the 9, 11, 13 dorsal plates pro- 

 duced; antennae, 33-43 joints (eastern U.S.) forficatus 

 3 . Posterior angle of the 7, 9, 11, 13 dorsal plates 

 produced ; 31-38 joints of antennas (southern 

 U.S.) . . . . , . . . spinipes 

 4 . Posterior angle of the 6, 7, 9, 11, 13 dorsal plates 

 produced ; joints of antennae, 14-23 (eastern 

 U.S.) . . . . . . multidentatus 



