Key to species of Allodrilus gen. nov. (with emphasis on males):

1 Pronotum mostly yellow or castaneus, often showing yellow spots or patches (Figs. 7–14, 22).........................2

1’ Pronotum variegated yellow, brown, and testaceous, usually showing two pairs of irregular V-shaped dark brown bands on metopidium (Figs. 15–21; 29–34)......................................................................... 5

2 Frontoclypeus entirely dark (Figs. 26–28); pronotum low, lateral margins broadly yellow (Figs. 10–14)................. 3

2’ Frontoclypeus concolorous with rest of vertex (Figs. 25, 35); pronotum moderately elevated and tectiform, mostly castaneous, testaceous or both (Figs. 7–9, 22).........................................................................4

3 Pronotum testaceous with yellow patches, dorsum feebly arched (Figs. 10–12); apex of frontoclypeus rounded (Figs. 26–27); branches of aedeagal apophysis bifurcate pre-apically (Fig. 84)............................ A. alboferrugineus sp. nov.

3’ Pronotum mostly yellow with dark brown patches, dorsum relatively straight (Figs. 13–14); apex of frontoclypeus acute (Fig. 28); branches of aedeagal apophysis not bifurcate pre-apically (Figs. 92–93)................... A. colombiensis sp. nov.

4 Vertex strongly concave below ocelli (Fig. 44); males: lateral plate strongly excavated medially, dorsal process triangular, strongly curved inwards, hook-shaped in caudal view (Figs. 125–126); branches of aedeagal apophysis with a ventral spine (Fig. 128)............................................................................. A. similis sp. nov.

4’ Vertex usually not strongly concave below ocelli (Fig. 37); males: lateral plate weakly excatated medially, dorsal process finger-shaped, slightly curved inwards (Figs. 72–73); branches of aedeagal apophysis lacking spines (Fig. 75)................................................................................... A. nitidipennis (Funkhouser) comb. nov.

5 Lower margins of vertex straight or feebly sinuate in frontal view (Figs. 29–31, 33–34); dorsum uniformly arched (Figs. 15–18, 20–21); males: branches of aedeagal apophysis apically directed upwards and sideways (Figs. 99, 106, 120).......6

5’ Lower margins of vertex strongly sinuate in frontal view (Fig. 32); dorsum relatively straight, posterior process constricted pre-apically (Fig. 19); apex of aedeagal apophysis curved downwards (Fig. 113).................. A. horizontalis sp. nov.

6 Males: Lateral plate dorsally arched, bearing small tubercle or tooth-like projection mostly visible in caudal view (Figs. 103–104, 115, 117–118); styles with small apical ventral lobe, curved sideways (Figs. 107, 121)....................... 7

6’ Males: Lateral plate dorsally sinuose, bearing finger-like elongated rectangular process, truncate apically, visible in lateral view (Figs. 95, 97); styles with ventral lobe inconspicuous........................................ A. deitzi sp. nov.

7 Males: lateral plate not distinctly inflated, dorsal projection hook-shaped, directed inwards, visible in both lateral and in caudal view (Figs. 103–104); branches of aedeagal apophysis slightly larger pre-apically (Fig. 106)......... A. granulatus sp. nov.

7’ Males: lateral plate inflated, forming round tubercle, as seen in lateral view (Fig. 117), with small round projection, visible only in caudal view (Fig. 118); branches of aedeagal apophysis not enlarged pre-apically (Fig. 120).. A. intermedius sp. nov.