CLAVICORNIA. 5 



Histeridte. This family is very well defined, and its members are, 

 with few exceptions, oval or obloug-oval insects, of a shining black or 

 brownish colour, glabrous, with the elytra sculptured with very distinct 

 striai ; the size is variable, some of the genera being rather large and 

 some (as Acritus) very minute ; the antennae are short, geniculate, and 

 usually received in grooves beneath the thorax, and terminate in a very 

 compact club ; the anterior coxal cavities are open behind ; the elytra 

 are truncate behind, leaving the pygidium and propygidium exposed ; 

 the abdomen is composed of five ventral segments, the first being the 

 largest ; the legs are short and retractile, with the tibiae compressed and 

 the anterior pair almost always toothed; the tarsi are 5-jointed (except 

 in Acritus and one or two other genera where they are heteromerous), 

 and the anterior pair at least are received in grooves on the tibias. 



Micropeplidae. This aberrant family has been by many authors 

 included under the Staphylinidas by reason of the much abbreviated 

 elytra : its present position, however, seems more natural ; the antennas 

 are received in a cavity beneath the margin of the thorax, and are 

 terminated by an obsoletely 3-jointed, almost solid, club; they are 

 inserted under the sides of the forehead ; all the coxae are distant, and 

 the anterior coxal cavities are open behind ; the abdomen is composed 

 of six segments ; the tarsi are very short, 3-joiuted, the last joint being 

 much longer than the rest ; the strongly-ribbed thorax, elytra and 

 abdomen will serve to distinguish our single genus, 



Nitidulidae. The characters of this family are very variable ; the 

 species are mostly small insects with the last one or two segments of the 

 abdomen very often, but by no means always, exposed : sometimes a 

 considerable portion of the abdomen is not covered by the elytra : the 

 antennae are inserted under the margin of the front, and are as a rule 

 11-jointed, and terminated by a 3 -jointed club; the maxillae (except in 

 the Brachypterina) are composed of one lobe ; the abdomen is composed 

 of five free ventral segments, except in a few genera, where the male has 

 an extra dorsal segment ; the tarsi are 5-jointed, except in the Khizo- 

 phagina, in .which they are heteromerous in the male ; the fourth joint 

 is always very small ; in shape the species vary from short and round or 

 ovate to long and cylindrical. 



Trog-ositidse. This family is closely related to the Nitidulidae, but 

 may easily be distinguished by the fact that the tarsi have the first joint, 

 and not the fourth, very small ; the maxillae have two lobes, and the 

 elytra always cover the abdomen. 



BXonotomidee. This family bears a considerable relation to the 

 Nitidulidae, but, apart from other characters, it may be distinguished by 

 the shape of the anterior coxae, which in the last named 'family are 

 transverse, and in the Monotomidse are rounded; the antennas are 

 inserted under the sides of the forehead, and terminate in a solid or 

 obsoletely 2-jointed club ; the head is large and the eyes are strongly 



