TRlCIIOPTERYGIDiE. 107 



Fam. XIV— trichopterygidae. 



Mentum quadrate. 



Maxilla3 exposed at the base, which is large, witli two 

 lobes, the inner one ciliate and hooked; palpi 4-jointed, last 

 joint acioular. 



Antennae inserted at the margin of the front, visually 

 11-jointed, verticillate with long hair, the first and second 

 joints thick, 3-7 slender, 8-11 thicker, forming a loosely 

 articulated, elongate club. 



Prothorax with the side pieces distinct. 



Elytra sometimes entire, sometimes abbreviated ; wings 

 long, narrow, margined with very long hairs ; sometimes 

 wanting. 



Abdomen with six or seven free ventral segments. 



Anterior coxte prominent, subglobular, contiguous; mid- 

 dle cox£e 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 

 two equal simple claws. 



The insects of this family are tlic smallest Coleoptera known. 



The table of genera, which have occurred in our fauna, has 

 been condensed from the monograph of the family by the Rev. 

 A. Matthews (Trichopterygia illustrata et descripta, London, 

 IS'IS), a work indispensable to any one who wishes to study these 

 minute and difficult insects : — 



Elytra not truncate. Ptiliini. 



Elytra trnncate. Trichopteeycini. 



Tribe I.— PTILIIIVI. 



Prothorax widest at base. 2, 



Prothorax widest in front of the base. 3. 



2. Pygidiunn concealed ; metasternum not extending to the sides of tin; 



body. Nossidium. 



Pygidium exposed ; angles of prothorax not elongated. Nanosella. 



3. Prothorax fitted to the base of the elytra. 4. 

 Prothorax at base extending over the Imnieri. Actidium. 



4. Metasternum extending to the sides of the body. b'. 

 Metasternum not extending to the sides of the body ; ,'). 



5. Prothorax not constricted at base. Motschulskium. 

 Prothorax narrowed at base. Micridium. 



