AMERICAN COLEOPTERA. 277 



Of the fifteen genera known in the tribe three only are found 

 outside of Europe and North America {Stereus Woll., from Madeira, 

 Dktta Sharp, New Zeahind, and Srotocri/pfus Girard, Brazil), the 

 remaining twelve are thus distributed : Peculiar to Europe Agari- 

 cophagus and Amphicj/Uis, peculiar to America Amgdus, Isoplastus 

 and Agli/ptus, leaving seven common to the two countries. 



The ten genera occurring in our fauna are distributed in the fol- 

 lowing manner : Peculiar to the Pacific region Triarthron, common to 

 the Atlantic and Pacific regions Hydnohius, Anisotoma, Liodes and 

 Agathidmm, leaving five occurring only in the Atlantic region. 



In the following table no mention is made of the contractile power 

 and any sexual difference in the tarsi has secondary mention, this is for 

 reasons already explained. In any cabinet arrangement Liodes should 

 be placed next in front of Agathidium, it is placed in the position it 

 occupies in the table on account of the antennal structure approaching 

 more closely the genera which precede it than those which follow. 



A. — Head without antennal grooves beneath. 



Posterior tarsi' 5-jointed. Mesosternum not cariuate. 

 Antennal club 3-jointed. 



Tibife slender, not strongly spinulose Triarthron. 



Tibiae dilated and strongly spinulose Stereus. 



Antennal club 5-jointed Hydnobius. 



Antennal club 4-jointed. 



Taisi 4—5—5 Dietta. 



Posterior tarsi with a less number than five joints. Mesosternum carinate. 

 Tarsi with joints 5 — 5 — 4 in both sexes. 



Antennal club 4-jointed .4nogdilS. 



Antennal club 5-jointed Anisotonia. 



Tarsi 5 — 4 — 4 in both sexes. 



Antennal club elongate, loose, 3-jointed Coleuis. 



Tarsi 4 — 3 — 3 in both sexes. 



Antennal club 5-jointed Agaricophagus. 



B.— Head with distinctly limited antennal grooves. 



Antennal club 5-jointed, elongate. Tarsi dissimilar in the sexes. ..L.iodes. 

 Antennal club 4-jointed. 



Antennae apparently 10-jointed. Tarsi similar in the sexes Cyrtusa. 



Antennae distinctly 11-jointed. Tarsi dissimilar "J, and $• ...Ainphicyllis. 

 Antennal club 3-jointed. Tarsi dissimilar in the sexes. 



Antennae 10-jointed Isoplastus. 



Antennae 11-jointed. 



Posterior tarsi 4-jointed in both sexes, the mesosternum not carinate 



between the coxae Agathidium. 



Posterior tarsi 3-jointed, mesosternum strongly carinate Aglyptus. 



The tribe as here constituted is composed of the same genera as 

 in those authors since the time of Lacordaire, he included Clambus 



