60 FAMILIES OF PETALOCERA WHICH LIVE 



Capitulo triphyllo, otato, transverso, lamellarum 

 disco utrinque sepius convexo. 



Labrum coriaceum, exsertum, scepius hirsutum. 



Mandibulae cornece, crassa, validrz, intus arcuata, inter- 

 dum dentatcc, apice acutissimo. 



Maxillse laciniis duabus, interna cornea unidentata vel 

 dentibus instructa, interdum unco corneo valido 

 processus hujus loco ; lacinia externa vel membra-' 

 nacea et vix fimhriata, vel cornea et ciliis spinuli- 

 formibus cut dentibus corneis armata. 



palpi maxillares maxillis longiores. 



Palpi labiales articuh ultimo ovato, plerumque crassi- 

 ore. 



Mentum irregidare. 



Caput subquadratum, Clypeo brevi, antice convexo. Cor- 

 pus ovatum, plerumque valde gibbum, subtus pla- 

 num ; Coleoptra maxima, gibboso-convexa, forni- 

 cata, ad latera undique dejiexa, ano ipso obvoluto. 

 Thorax transversus ; Scutello distincto. Pedes 

 forma variantes ; tibiis anticis sape dentibus haud 

 munitis. 



Observations. 



The Trogidce, tliough by no means a family having such 

 strono" general characters impressed on it as either of those 

 we have hitherto considered, may nevertheless be distin- 

 guished from them all ^vith considerable facility. Their 

 antennse in the first place have the lamella of their clava 

 convex on both sides ; so that the three joints of which this 

 is composed are always very distinct; whereas in the Geo- 

 trupida the first and second joints of the clava are one or 



