DERMESTIDAE. 105 



male having but three joints. The frontal suture is always dis- 

 tinct, and usually deep. 

 Our genera are : — 



Eyes transverse ; 



Antennae gradually enlarged externally. Mycetophagus. 



Antenna? with joints 9 — 11 suddenly larger. Triphyllus. 



Eyes rounded ; antennae with joints 9 — 11 suddenly larger; 



Clypeal suture not deeply impressed. Litaegus. 



Clypeal suture deep. Typhjea. 



Eyes rounded ; antennae with joints 10 — 11 suddenly larger. Beeginus. 



Mycetophagus and Litargus are generally diffused ; Tijphsea 

 fumata has been imported by commerce, and is found in houses ; 

 Triphyllus ruficornis Mels. is found in the Atlantic district. 

 Berginus occurs in Pennsylvania. 



Sub-Family II.— DIPHYLLIDAE. 



This sub-family contains a very small number of species, agree- 

 ing in form with those of the preceding sub-family, but coarsely 

 punctured, with less fine and less prostrate pubescence. The 

 anterior coxal cavities are closed. The tarsi are 5-jointed, but 

 the fourth joint is small, and the third prolonged beneath, form- 

 ing a membranous lobe. 



The genus Diphyllus has but the tenth and eleventh joints of 

 the antennae enlarged, and has not yet occurred in our fauna. 

 Our genera have the club of the antennas 3-jointed, and are 

 known as follows : — 



Thorax without elevated lines. Marginus. 



Thorax with two fine longitudinal lines near the sides. Diploco5lus. 



The last joint of the antennae is somewhat narrower than the 

 tenth in Marginus, and is of the same breadth in Diploccelus. 

 They are each represented by one species in the Atlantic States. 

 I found a species of either Diploccelus or Diphyllus in Arizona, 

 but the specimen has been lost. 



Fam. XXVI.— DERMESTIDAE. 



Mentum quadrate, usually corneous ; ligula simple ; palpi 

 short, 3 -jointed. 



