HISTERIDAE. T3 



Fam. XL— HISTERIDAE. 



Mentum corneous, sometimes large and covering the base 

 of the maxillae, flat or slightly concave, subquadrate, some- 

 times emarginate or tridentate in front; ligula almost con- 

 cealed behind the mentum; palpi 8-jointed, cylindrical. 



Maxillae with two ciliated lobes, the internal one much 

 smaller; palpi 4-jointed, cylindrical. 



Antennas geniculate, capable of being retracted, short, in 

 the second sub-family with the first joint thick, but in the 

 first with the first joint long, the eighth and following ones 

 forming a compact, annulated, rounded, or (rarely) triangular 

 club. 



Prothorax closely applied to the elytra ; side pieces not 

 distinct;* in most of the genera with two cavities to receive 

 the club of the antennas; prosternum frequently lobed in 

 front, produced behind, articulating with the mesosternum; 

 coxal cavities open behind. 



Mesosternum separating widely the middle coxae; side 

 pieces large, not divided, sometimes visible from above. 



Metasternum very large, almost connate with the meso- 

 sternum anteriorly; episterna sometimes narrow, sometimes 

 broad, occasionally curved ; epimera broad, large, separated 

 by a fine suture, which is sometimes effaced. 



Elytra truncate behind, leaving two segments of the ab- 

 domen uncovered ; scutellum small in the first sub-family, 

 entire in the second. 



Abdomen with five free ventral segments, the first very 

 large, the fifth very short, closely applied to the last dorsal 

 segment, which is triangular and deflexed. 



Anterior coxae transverse and not prominent in the first 

 sub-family, globose in the second; middle and posterior coxae 

 widely separated, not prominent, rounded, or rather sub- 

 quadrate, the latter not extending to the sides of the body. 



Legs short, retractile; tibiae compressed, anterior ones 

 usually toothed, posterior sometimes toothed; spurs distinct, 

 those of the anterior pair very unequal. Tarsi slender, short, 

 5-jointed in the first sub-family (except in Acritus, where 

 the posterior ones are 4-jointed), 4-jointed in the second sub- 

 family; claws (in all of our genera) two, simple; anterior tarsi 

 usually received in grooves on the anterior face of the tibiae. 



* In some species there is an elevated line, simulating a suture. 



