136 COLEOPTERA OF NORTH AMERICA. 



is entirely wanting; the ventral segments are connate, and the 

 sixth is indistinct ; the last spiracle is on the suture between the 

 propygidium and fifth ventral. 



Sub-Tribe 2.— Diclielonychini. 



The genus Dichelonycha alone represents this sub-tribe in our 

 fauna, but is universally distributed. It is distinguished from va- 

 rious foreign sub-tribes having prominent anterior coxae, distinct 

 labrum, and separate ventral segments, by the ligula connate with 

 the mentum, the large vertical and deeply emarginate labrum, 

 and by the sternum not being prominent. The last spiracle is 

 placed outside of the suture between the propygidium and the 

 fifth ventral segment, which are not connate to form a solid ring. 



From Macrodactylini it differs by the position of the last abdo- 

 minal spiracle ; by the claws being chelate, or capable of being 

 folded along the last joint of the tarsi, though they are not usually 

 seen in that position ; and by the large, prominent eyes. 



In Dichelonycha the thorax has a narrow anterior membranous 

 margin, and the claws are equal and cleft at tip. 



They are elongate hairy insects, usually of metallic color, some- 

 times found in large numbers on leaves of trees. 



Sub-Tribe 3. — Sericini (genuini). 



This sub-tribe is also represented in our fauna by a single 

 genus, Serica, of universal distribution. They are oblong, con- 

 vex insects, of a brown color, usually with iridescent reflections ; 

 the elytra are indistinctly sulcate ; the pygidium is sometimes 

 partly covered by the elytra. 



It is readily distinguished from all others of this family by the 

 labrum being connate with the under surface of the clypeus, and 

 therefore indistinct. 



The fifth ventral segment and the propygidium are separated 

 by a distinct suture, and the spiracle is placed external to this 

 suture, half way between the anterior and posterior margin of 

 the ventral segment. The posterior coxa? are flat, and broadly 

 dilated. 



Sub-Tribe 4.— Ma crodactylini. 



Three species of Macrodactylns, distributed from the Atlantic 

 to Arizona, 'alone represent this group in our fauna; they are 



