64 ARTHROPODS 



EE. Abdomen with six ventral segments. 



F. Ventral abdominal segments free Silphidae. 



DD. Tarsal claws pectinate Cistelidae. 



CC. Anterior coxal cavities open behind. 

 D. Head not strongly and suddenly constricted at base. 

 E. Middle coxae not very prominent. 

 F. Antennae free. 

 G. Prothorax margined at the sides. 

 H. Epimera of mesothorax reaching the coxae. 



I. Metasternum long; epimera of metathorax 

 visible Melandryidae. 



II. Metasternum quadrate; epimera of metathorax 

 covered Cucujidae. 



DD. Head strongly constricted at base. 

 E. Head suddenly narrowed behind. 

 F. Prothorax with the side pieces not separated from the 

 pronotum by a suture. 



G. Tarsi perfect with distinct claws; eyes normal. 

 H. Prothorax at base narrower than the elytra. 

 I. Hind coxae large, prominent. 

 J. Claws cleft or toothed; front vertical. 



Meloidae. 

 HH. Prothorax, at base, as wide as the elytra. 



Rhipiphoridae. 

 FF. Lateral suture of prothorax distinct ; base of pro- 

 thorax as wide as the elytra. 

 G. Antennae filiform. 



H. Hind coxae platelike Mordellidae. 



HH. Hind coxae not platelike Melandryidae. 



AA. Head more or less prolonged into a beak; palpi short and 

 rigid ; gular sutures confluent on the median line ; prosternal 

 sutures wanting; the epimera of the prothorax meeting on the 



middle line behind the prosternum ._ RynclwptJwra. 



B. Elytra with no fold or with a very feeble one on the lower 

 surface near the outer edge ; pygidium of male and female alike. 



C. Labrum distinct Rhinomaccridae. 



CC. Labrum wanting. 



