80 COLEOPTERA OP NORTH AMERICA. 



Anterior coxae prominent, subglobular, contiguous; middle 

 coxae oval, not contiguous; posterior transverse, more or less 

 separated, sometimes dilated over the feet into a flat plate. 



Legs moderate, slender; tarsi 3-jointed, last joint with a 

 long bristle with a clubbed tip between the ungues. 



The insects of this family are the smallest Coleoptera known; 

 those found in this country have not yet been studied with care, 

 and but few are described, although there are in my collection 

 twenty-eight species. 



All the genera of the family are represented in our fauna, as 

 follows : — 

 Posterior coxae approximated, laminate ; first ventral segment acuminate in 



front. Nossidium.* 



Posterior coxae widely distant ; first ventral segment truncate in front ; 



Antennae with the last three joints thickened ; 



Posterior coxae laminate (body pubescent). Tkichopteryx. 



Posterior coxae simple (body pubescent). Ptilium. 



Antennae with the last two joints thickened. Ptenidium. 



Fam. XIV.— phalacrid ae. 



Mentum corneous, flat, of a different form in each genus, 

 but all derived from the quadrate form. 



Maxillae with two lobes, internal one coriaceous, with two 

 small terminal teeth ; the outer corneous, ciliate at the tip" 

 which is coriaceous. 



Antennae inserted under a slight frontal margin, 11-jointed, 

 the last three joints forming an oval club. 



Prothorax with the side pieces not distinct ; prosternum 

 prolonged, entering the emarginate mesosternum behind ; 

 coxal cavities not closed behind. 



Mesosternum very short, side pieces large, not distinctly 

 divided. 



Metasternum large, produced anteriorly, side pieces nar- 

 row, partly concealed by the sides of the elytra. 



Elytra rounded at tip, entirely covering the abdomen. 



Abdomen with five free ventral segments, not differing 

 much in length, the first somewhat longer. 



Anterior coxae globular; middle coxae transverse, sepa- 

 rated by the sternum ; posterior contiguous, transverse, fiat. 



* I do not possess any species of this genus. One was discovered by 

 Mr. Motschulsky, in Alabama. 



