GEORYSSIDAE. 113 



third joint lobed ; claws dilated at base. Epipleurse very narrow, 

 extending to the apex, grooved to fit the margin of the body. 



It might perhaps be properly considered as a distinct family, 

 but its affinities with the Byrrhidae are none the less evident; 

 though it is a transition form to the Helodidae, below described. 



Fam. xxviil— georyssidae. 



Mentum quadrate, corneous, moderately large; ligula co- 

 riaceous, slightly bilobed. 



Maxillas with two unarmed lobes. 



Antennge inserted under the sides of the front, near the 

 eyes, 9-jointed, the first and second joints thick, the last three 

 forming an oval club. 



Head deflexed ; labrum distinct ; mandibles small ; eyes 

 rounded, lenses large. 



Prothorax with the side pieces not distinct; presternum 

 membranous, not visible between the coxee ; flanks excavated 

 for the reception of the antennas. 



Mesosternum short and wide, pf/pendicularly declivous in 

 front. 



Metasternum moderjjfely largie, side pieces very narrow. 



Llytra entire, descending widely on the flanks ; epipleural 

 fold narrow, extending to the ape:<. 



Abdomen with five free ventral ^egments.^ 



Anterior coxae prominent, flattened at tip, forming two 

 small, subquadrate, contiguous plates, with a deep fissure 

 between them, in which is concealed the presternum ; middle 

 coxae oval, distant; posterior transverse, not contiguous. 



Legs short, slender; tarsi filiform, 4-joiuted, the first joint 

 longer than the following two ; claws simple, small. 



This family consists of but one genus, G-eoryssu.s ; of it several 

 ipecies are found in Europe and Asia, and one in Kansas, G. 

 l>n villus Lee. 



They are small, rounded, convex, roughly sculptured, black 

 insects, found at the margin of streams, on wet sand ; they cover 

 themselves with a mass of mud, so that no part of the insect is 

 visible. 



