SILPHIDAE. 51 



the elytra are strongly truncate, and striate ; the antennae are 

 slightly geniculate*:!, with the first joint much elongated ; the 

 club is rounded, composed of three joints. The appearance is 

 very similar to Hister. 



This genus has been placed by Redtenbacher in Nitidulidae, 

 but the form of the anterior coxae is altogether different, and 

 entirely similar to that seen in the present family, in which it is 

 retained by other systematists. But the difference in the abdo- 

 men seems to me to indicate a separate sub-tribe. 



Tribe II.— ANISOTOMIKI. 



Body oval, convex, sometimes hemispherical, sometimes capable 

 of being contracted into a ball. Mandibles with a basal molar 

 tooth. Antenna? 11-jointed, clubbed, the eighth joint frequently 

 smaller than the contiguous ones. Epimera and episterna of 

 metathorax covered by the elytra. Posterior coxae contiguous ; 

 their trochanters not prominent inwardly. Tarsi variable. 



This tribe consists of small species, which live either in decom- 

 posing fungi, or under the bark of dead trees. 



A. Tarsi with the same number of joints in both sexes ; body not at all 



contractile ; 

 All the tarsi 5-jointed ; eighth joint of antennae small. Hydnobius.* 

 Anterior and middle tarsi 5-jointed, posterior 4-jointed ; 



Mesosternum carinate ; eighth joint of antennae small. Anisotoma. 

 Mesosternum flat; eighth joint of antenna hardly distinct. 



Cyrtusa. 

 Anterior tarsi 5-jointed, middle and posterior 4-joiuted ; club of an- 

 tennae 3-jointed. Colenis. 



B. Tarsi dissimilar in the two sexes ; body more or less contractile ; 



Club of antennas 5-jointed, eighth joint small. Liodes. 



Club of antennae 3-jointed. Agathidium. 



Tribe III.— CLAMBIIVI. 



Body oval, capable of being more or less contracted into a ball. 

 Antennae 9- or 10-jointed, clubbed. Episterna of metathorax not 



* I introduce this genus on the authority of Erichson, who referred 

 (Wiegm. Archiv, 1S47, ii. 100) to it Liodes alternate Mels., which, however, 

 I find to have only 4-jointed posterior tarsi, and have accordingly placed it 

 in Anisotoma. Nevertheless, it is quite possible that Erichson may have 

 had before him a genuine species of Hyduobius, unknown to mo. 



