MANUAL OF NATURAL HISTORY. 181 



drate, margined; legs long, tibiae slender, 

 not spinose ; tarsi 5-jointed. Live under 

 stones in running streams. 



13. FAMILY. Herbivorous Water-Beetles (Helopho- 



ridae). Antennae 9-jointed, perfoliate, cla- 

 vate ; club sub-serrated ; mandibles not tooth- 

 ed at tip ; maxillary palpi very long ; body 

 oblong, flattish ; thorax sub-quadrate ; tibiae 

 slightly spinous ; tarsi 5-jointed, filiform, not 

 ciliated, basal joint minute. Inhabit ponds 

 and ditches ; herbivorous in the perfect state. 



14. FAMILY. Water-Beetles (Hydrophilidae). An- 



tennae 6 9-jointed, perfoliate, clavate, club 

 distinctly cleft, mandibles bidendate at tip ; 

 maxillary palpi very long, filiform ; body 

 oval or globose ; thorax short, transverse ; 

 tibiae slightly spinose ; tarsi 5-jointed, fili- 

 form, hind pair often ciliated Frequent the 

 water, fly abroad in the evening. 



15. FAMILY. Excrement-Beetles (Sphaeridiidae). An- 



tennae short, 9-jointed, basal joint very long, 

 four next short, the rest forming a com- 

 pressed perfoliate club ; maxillary palpi as 

 long as antennae, second joint thickened, 

 head round in front ; thorax transverse ; 

 body more or less hemispheric ; tibiae com- 

 pressed, spinose ; tarsi filiform ; claws two, 

 unequal Living in the excrement of vari- 

 ous animals. 



16. FAMILY. Armadillo - Beetles (Agathidiidae). 



Antennae 11-jointed, rather long, slender at 



