1.
.		 Head with surface not setose, variously sculptured, may have with setal fringe on clypeus (Fig. 1)

.
2
 

1'.
.
.

 Head with surface distinctly setose (Fig. 2)
.
.
Figure 1. Aegialia argentina.
Figure 2. Argeremazus neuquen.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2(1).
.
.		 Elytral intervals with short hair. Abdominal sternites narrowed medially, fifth sternite obliterated at middle by sixth sternite (Fig. 3)

..

Micraegialia Brown

Figure 3. Micraegialia pusillus.

2'.
.
.

 Elytral intervals lacking short hair. Abdominal sternites not narrowed medially, fifth sternite not obliterated at middle by sixth sternite
.

. 3
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3(2).
.		 Elytral humerus dentate (Fig. 4). Body form parallel-sided


. 4
 

3'.
.

 Elytral humerus not dentate (Fig. 5). Body form elongate to globose

. 5
Figure 4. Amerisaprus valdivia.
Figure 5. Aegialia argentina.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4(3).
.
.		 Pronotum with posterior angle eroded, bearing several small teeth (Fig. 6). Apical metatibial spurs not separated at base. Body black. Chile

Amerisaprus Stebnicka and Skelley

Figure 6. Amerisaprus valdiviana.

4'.
.
.
.

 Pronotum with posterior angle not notably eroded, lacking distinct teeth. Apical metatibial spurs separated at base by metatarsus. Body reddish-brown Western North America and Japan
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5(3).
.
.
.
.		 Maxillary palpus with terminal segment enlarged, widest at basal third, abruptly narrowed at base. Body red-brown. Body form notably elongate, almost parallel-sided. Basal marginal line of pronotum indistinct or lacking

.
.
.
.
Rhysothorax Bedel
 

5'.
.
.
.
.

 Maxillary palpus with terminal segment cylindrical. Body usually black, reddish-brown in some flightless members. Body form elongate to globose, but not parallel-sided. Basal marginal line of pronotum usually distinct, at least laterally