118 THE ORDER OP COLEOPTERA. 



America: Sfylops, Kirby, with the antennae six-jointed ; and Xenos, Eossi, 

 having the antennte four-jointed. For a detailed description of these 

 insects the reader is referred to Westwood's Introduction, Vol. ii, page 

 287 ; or to I'ackard's Guide, page 481. 



Tribe XHI. 



HETERpMEROUS BARK-BEETLES. 

 Heteromera corticicola. Stenelytra partly, Latreille. 



This tribe includes all the Stenelytra of Latreille except the family of 

 Helopidie, which are now united to the Ground-beetles. The word Sten- 

 elytra means Laving narrow icing-covers, and was given to these insects 

 on account of their more or less elongated and narrow forms. They are 

 distinguished from the parasitic beetles by the absence of a visible neck 

 and by tlie head being narrower than the thorax; and from the two 

 following tribes by the usually longer and more slender antenme, by 

 the anterior coxte nearly or quite touching each other, and by their 

 coxal cavaties being open behind, except in Cistelidaj where they are 

 slightly closed. The larvsB of all these insects are found under the bark 

 or in the decayed wood of trees which have been long dead. The per- 

 fect insects are generally found in the same situations, but some, especi- 

 ally the CistelidfB, are often seen upon leaves or flowers. 



The following are the families of bark-beetles : 



A. Thorax rounded at the sides, or without a sharp htteral margin, narrower behind 

 tlian in front, and narrower at base than the elj'tra. 

 B. Head gradually narrowed behind, and usually somewhat prolonged in front; 



last joint but one of tarsi slight]}^ bilobed (Edemerid.e. 



B B. Head not narrowed behind; sometimes prolonged in front into a snout; 



tarsi entire Pythid.^. 



A A. Thorax with a lateral margin, not narrowed behind, and usually as wide at 

 base as the elytra. 

 C. Maxillary palpi terminating in a hatchet-shaped joint; claws serrate: 



ClSTELID^ . 



C C. Maxillary palpi usuall}' long and pendulous, with all their joints more 

 or less enlarged ; claws simple Melandryid^. 



Family XLIX. (EDEMEKIDiE. 



A small family of heteromerous beetles, with elongate, narrow bodies, 

 the head and thorax somewhat narrower than the elytra, and rather 

 long filiform antenna?. The elytra in some of the foreign species are 

 narrowed and separated behind. Our most conspicuous species is the 

 Nacerdes melanura, which is more than half an inch in length, of a yel- 

 lowish-brown color, with the elytra tipped with black. 



