Dorsal plates with two points behind; first pair of legs reduced 

 Scolopendrella Gervais 



KEY TO THE COMMON GENERA OF DIPLOPODA 

 OR MILLIPEDES 



L Integument soft; animals cannot roll into a hall or spiral 

 Polyxen-idae, Polyxenns Latreille 

 Integument stiff; usually capable of rolling into a ball or spiral 2. 



2. Mouth parts suctorial Polyzoniidae 3. 

 Mouth parts biting 4. 



3. With eyes 



Polyzonium Brandt 

 Without eyes 



Platydesmns Lucas 

 (Brachycyhe Wood) 



4. With nineteen to twenty-one segments; body usually flattened; 



Polydesmidae 

 With more than twenty-five segments; body cylindrical IL 



5. With a deep transverse furrow on the dorsal plates 



Oxidus Cook 

 (Paradesmus Saussure) 

 No transverse furrows on dorsal plates 6. 



6. With a spine on the lower side of the base of each leg 



Fontaria Gray 

 No spines on bases of legs 7. 



7. Anal segment truncate; body usually brightly spotted 



Eurynrus Koch 

 Anal segment pointed behind 8. 



8. Tubercles absent or scattered on dorsal plates 9. 

 Tubercles in two to five transverse rows on dorsal plates 10 



9. Back curved; color brown 



Leptodesynus Saussure 

 Back more flattened; color white 

 Chaetapsis BoUman 



10. With two or three rows of tubercles across the dorsal plates 



Scytonotus Koch 

 With four or five rows of tubercles across the dorsal plates 

 Polydcsmus Latreille 



1 1 . Segments twenty-six to thirty; anal segment ending in two papillae; 



Craspedosomidae 12. 



Usually with more than thirty segments; anal segment curved or ending 



in a spine 17. 



12. Adult segments twenty-eight 



Trichopetalum Harger 



218 



