LAND SCAVENGER-BEETLES. 59 



The following are the three typical genera : 



A. Head porrected ; mandibles as long as the head ; body very flat ; size comparatively large — 



HOLOLEPTA. 



A A. Head retracted ; mandibles short ; body usually convex, (flattened in sub-genus Paromalus.) 



B. Prosternum advanced so that the head is invisible from beneath Hister. 



B B. Prosternum not advanced Sai'KLNUS. 



Sister is divided by Dr. LeConte into ten lesser genera, which De 

 Marseal has still further subdivided so as to form four additional ones. 

 These divisions are made in accordance with slight organic variations, 

 w hich however are sometimes accompanied by differences in size, or by 

 perceptible modifications of the general form. 



More recently, Dr. Geo. H. Horn has contributed to the American 

 Philosophical Society (June, 1873,) a valuable synopsis of the Histeridas 

 of the United States, in which all our species are carefully reviewed 

 and described. 



Family X. NITIDULID^. 



The typical insects of this family constitute the genus Nitidula of 

 Fabricius, a word literally meaning shining, or elegant, but which is sin- 



rFig.21.] gularly inapplicable to the insects of this family, as now- 

 constituted, most of which are clothed with a fine pube- 

 scence, which is incompatible with a shining surface. They 



'^ are small, somewhat flatteued beetles, the thorax having a 

 wide, thin margin, and the wing-cases more or less cut off 

 NiTiDLLA :- 1. bchlud, SO as to leave the end of the abdomen exposed. In 

 sx^sTa'an^M-" the sub-family of Carpophilides, the elytra are so short as 

 Ave^wood.'' ' to leave two or three of the abdominal segments uncovered, 

 but in the Isitidulides only the tip of the abdomen is exposed. The 

 fourth tarsal joint is very small, and wholly wanting in the hind tarsi 

 of the males of some species. Their colors are usually brown or black- 

 ish, with or without dull yellow spots. 



The insects of this family vary much in their habits. Some are found 

 on carrion and others on flowers ; several of the most common species 

 are often met with on apples and other fruit in a state of decay. The 

 larva} of the genera Ips Carpophilus and Rhiozophagus, have been 

 show^n by the observations of a French author, M. Ed. Ferris, to be car- 

 nivorous, subsisting upon soft, sub-cortical larvse. 



Ninety N. A. species have been described, under the following prin- 

 cipal genera : 



A. Anteonse ll-jointed, club 3-Jointed; body oval. 

 B. Only the tip of the abdomen exposed. 

 C. Surface pubescent ; colors dull ; upper lip exposed. 

 D. Body depressed , thorax not overlapping the elytra ; color brown, usually with obscure yel- 



,' _„,i., NiTIDULA. 



low spots 



D D. Body convex; thorax slightly overlapping the base of elytra. Color brown, usually shaded 



_.!, ,, ,, Cychramus. 



with black 



O C. Surface smooth and shining ; color black, spotted with yellow or reddish ; labrum concealed : 



B B. Two or three last segments of abdomen uncovered by elytra Carpophilus. 



AA. AntennajlO-jointed; clubsoUd; body elongated Ehizophagus. 



