1.
.

 Mesotibia with subapical notch and tooth on inner margin (Fig. 1)

.
2
 
1'.
.
 Mesotibia with inner margin entire; if present, mesotibial tooth at apex (Fig. 2)
.
3
Figure 1. Aschnarhyparus peregrinus
Figure 2. Rhyparus mexicanus
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

2.
.

 Metatibial apex fringed with distinctly unequal spinules, mixed short and long (Fig. 3). Elytral intervals often dull

.
2
 
2'.
.
 Metatbial apex fringed with short spinules of eqaul length (Fig. 4). Elytarl intervals shiny
.
3
Figure 3. Diapterna hamata. Figure 4. Teuchestes fossor.
Figure 3.Diapterna hamata.
Figure 4. Teuchestes fossor.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2(1).
.
.		 Meso- and metatibiae flattened, triangular in cross section (Fig. 3). Pronotal carina sharp, uniform height throughout length

.
Aschnarhyparus Makhan
 
2'.
.
.		 Meso- and metatibiae more cylindrical, circular in cross section (Fig. 4). Pronotal carina swollen; more prominent, bulbous anteriorly
Figure 3. Aschnarhyparus peregrinus
Figure 4. Termitodius coronatus
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3(1).
.		 Elytra not parallel-sided (Fig. 5), short, not more than 2 times longer than pronotum

Nanotermitodius Howden
 
3'.
.		 Elytra parallel-sided, long, but 2.5 times longer than pronotum (Fig. 6)
.
4
Figure 5. Nanotermitodius peckorum,
from Howden 2003. Thanks and credits to Jennifer Read, Agriculture Canada
Figure 6. Rhyparus opacus
x
x
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4(3).
.		 Discomedial carina of elytra lacking distinct setal tuft immediately anterior of apical trichomes

Rhyparus Westwood
 
4'.
.
.		 Discomedial carina of elytra with distinct, narrow setal tuft immediately anterior of apical trichomes (Fig. 7-8)
Figure 7. Leptorhyparus sp.
Figure 8. Leptorhyparus sp.