PTINIDAE. 207 



sometimes obsolete ; the fifth joint is long, with simple claws. 

 The first ventral segment is but slightly longer than the second. • 

 Three tribes are indicated : — 



Thorax with distinct lateral margin. ' Exdecatomini. 

 Thorax without lateral margin ; 



Head covered by prothorax ; anterior coxse contiguous. Bostkichini. 



Head prominent ; anterior coxae distant. Psoim. 



Tribe I.— ENDECATOMINI. 



The genus Endecatomus, placed by previous authors in the 

 family Cisidae, seems to me, for reasons indicated below, to belong 

 rather to the present, in which it constitutes a distinct tribe. 



The head is covered in part by the prothorax, which is dis- 

 tinctly margined at the sides. The epistoma is separated from 

 the front by a very distinct suture ; the antennae are 11-jointecl, 

 with a loosely articulated 3-jointed club. The anterior coxa? are 

 prominent, and contiguous ; the terminal spur of the anterior 

 tibiae is large and hooked. The last joint of the tarsi is very long. 



The species known to me, Endecatomus rugosus, is an oblong 

 convex blackish-brown dull insect, covered with inequalities and 

 small erect brown hairs ; it is less than one-fifth of an inch long, 

 and is found in fungi. It seems to have but little relation to the 

 Cisidae, but to be rather a connecting link between Bostrichus 

 and Anobiuni. 



Tribe II.— BOSTRICHI1VI. 



The insects of this tribe are moderate in size, or small, of a 

 cylindrical form, with the head deflexed, prolonged behind the 

 small prominent eyes, and covered by the hood-like prolongation 

 of the prothorax ; the epistoma is separated by a moderately dis- 

 tinct suture ; the anterior portion of the latter is usually rough 

 with tubercles, and in the genus Bostrichus is frequently pro- 

 longed, forming two short horizontal horns ; the anterior coxal 

 cavities are confluent ; the hind part of the elytra is frequently 

 obliquely declivous. The antenna; have 10 joints in our genera, 

 and the club is 3-jointed. The external margin of the anterior 

 tibiae is more or less serrate in all of our genera. 



Our genera are found in fungi, and under bark: — 



Intermediate joints of antenna? shorter than the first and second; 

 Joints 8 — 10 very long, forming a serrate club. Sixoxylon, 



