KEY TO MALES OF THE OBLIGATE ACACIA-ANTS,

PSEUDOMYRMEX FERRUGINEUS GROUP

Although isolated acacia-ant males are unlikely to be encountered, the following key is offered as a supplement for determination of species in the P. ferrugineus group. It can be used to confirm workeror queen-based identifications, but some couplets require examination of the male genitalia.

1. Posterior margin of subgenital plate (stemite IX) with a shallow (less than semicircular) concavity (Fig. 54); scape short, SI2 0.33-0.43, SL/HL≤0.21 .......................................................................2

- Posterior margin of subgenital plate (stemite IX) with a deep, semicircular concavity (Fig. 55); scape longer, SI2 0.43-0.56, SL/HL≥0.22 ...............................................................................................3

2. Paramere, in lateral view, with a slender finger-like mediodorsal lobe and angulate posteroventral comer (Fig. 57)................................................................................................................... particeps

- Paramere, in lateral view, with a stubbier mediodorsal lobe and more gently rounded posteroventral comer (Fig. 56).............................................................................................................. nigrocinctus

3. Scape and compound eye longer, relative to HW (SI 0.29-0.35; REL2 0.56-0.62 (n=6)); head narrower, Cl 0.82-0.94, HW 0.81-0.95; lateral view of paramere as in Figs. 58a, 58b peperi

- Scape and compound eye shorter (SI 0.22-0.30, REL2 0.49-0.58); head broader, Cl≥0.94 and/or HW≥0.96; lateral view of paramere not as in Figs. 58a, 58b ................................................................4

4. Paramere, in lateral view, with posterodorsal comer well separated from mediodorsal lobe (Figs. 59- 60)....................................................................................................................................................5

- Paramere, in lateral view, with posterodorsal corner bent upward and enclosing a space between itself and the mediodorsal lobe which is subequal to the area of the latter (Figs. 61-65)........................6

5. Lateral view of paramere as in Figs. 59a and 59b: mediodorsal lobe relatively broad and partly enclosing a space between itself and the posterodorsal comer; larger species, HW 1.06-1.09 (n=5)................................................................................................................................... satanicus

- Paramere typically as in Fig. 60a, with mediodorsal lobe more slender and more distant from posterodorsal comer (Fig. 60b depicts a less typical male, from Colombia); smaller species, HW 0.92- 1.05 (n=12)......................................................................................................................... spinicola

6. Mediodorsal lobe of paramere stout, directed more or less dorsally (Figs. 61, 62)........................7

- Mediodorsal lobe of paramere more slender and directed posterodorsally (Figs. 63-65)...............8

7. Body pubescence dense and conspicuous, suberect on dorsum of head, propodeum and petiole; smaller species, HW 0.79-0.88 (n=7)................................................................................. veneficus

- Body pubescence less dense and less conspicuous, predominantly appressed or decumbent on the propodeum and petiole; larger species, HW 0.88-0.97 (n=6)............................................. mixtecus

8. Smaller species, HW 0.93-0.96 (n=6).................................................................................... janzeni

- Larger species, HW 0.99-1.19 (n=22).................................................... ferrugineus and flavicornis