Key to the species of Alloeorhynchus known from Mexico

1 Anterior lobe of pronotum shiny yellow or yellowish orange, or golden orange..................................... 2

- Anterior lobe of pronotum shiny black or shiny reddish brown or pale brownish castaneous........................... 9

2 Connexival segments II–V shiny yellow with a group of black spinules resembling an elongate spot.................... 3

- Connexival segments entirely shiny yellow................................................................. 6

3 Clavus shiny yellow with punctures and apical third shiny castaneous; corium yellow with apical third shiny pale castaneous (Figs. 4, 19–20).......................................................................... A. macer sp. nov.

- Clavus and corium mostly black to reddish brown............................................................ 4

4 Posterior lobe of pronotum shiny yellowish orange to reddish orange with three black marks, one at each posterior angle and along lateral edge and a triangular-shaped one at base of midline (Figs. 2–3, 17–18).................. A. trimacula (Stein)

- Posterior lobe of pronotum not distinctly trimaculate.......................................................... 5

5 Posterior lobe of pronotum shiny yellowish orange except for a black semilunar area medially on posterior margin, almost touching the posterior border of anterior lobe; collar shiny yellow or yellowish orange (Figs. 6–7, 11–12)................................................................................................... A. nigrofasciatus Harris

- Posterior lobe of pronotum shiny black to reddish brown except for wide yellowish orange triangular mark lateral to middle line; collar shiny reddish brown (Fig. 10).................................................. A. vergrandis sp. nov.

6 Prothorax including the acetabulae shiny yellow; lateral margin of anterior lobe of pronotum shiny yellow............... 7

- Prothorax shiny black to reddish brown with acetabulae yellow; lateral margin of anterior lobe of pronotum shiny pale castaneous to reddish brown or black............................................................................ 8

7 Posterior lobe of pronotum shiny yellow with posterior border and lateral borders of humeri shiny reddish brown.............................................................................................. A. bellatulus sp. nov.

- Posterior lobe of pronotum shiny reddish brown (Figs. 9, 13–14)............................... .. A. nigrolobus Barber

8 Head dorsal and ventrally shiny black to reddish brown; posterior lobe of pronotum shiny reddish brown (Figs. 21–22)........................................................................................... A. epigaeus sp. nov.

- Head dorsally shiny castaneous to golden orange with apical third yellow; head ventrally shiny yellow; anterior and posterior lobe of pronotum pale golden orange with lateral edge and humeri black (Figs. 1, 15–16)............... A. aureus sp. nov.

9 Corium yellow with apical third reddish brown; legs yellow; apex of scutellum reddish brown; antennal segment IV pale castaneous to pale castaneous orange (Fig. 8)...................................................... A. moritzii (Stein)

- Corium brownish castaneous; legs dark castaneous (tarsi pale castaneous); apex of scutellum yellow; antennal segment IV yellowish white with basal third and apex brown (Fig. 5)........................................ A. convolutus sp. nov.