Key to males of the Neotropical species of Dasydorylas

1. Postpedicel with acuminate apex (Fig. 29); vein M 1 slightly straight or clearly straight (Fig. 31) ........................................................................................................................................................... 2

– Postpedicel with aristiform apex (Figs 3, 16, 42); vein M 1 slightly to clearly upward curved (Figs 5, 18, 44) ............................................................................................................................................... 7

2. Phallus bifid [fig. 36 in Rafael & Ale-Rocha (2004)] ................................ D. vulcanus Rafael, 2004

– Phallus trifid [Figs 12, 25, 51) .......................................................................................................... 3

3. Both surstyli with bases slightly thicker than apices [fig. 25 in Rafael (1991)]; third costal section subequal in length to fourth [fig. 39 in Rafael (1991)] ............................... D. regalis (Rafael, 1991)

– Both surstyli with bases clearly thicker than apices (Fig. 34); third costal section slightly longer than fourth (Fig. 31) .................................................................................................................................. 4

4. Left surstylus left-directed and right surstylus directed clearly downwards, when seen in frontal view [fig. 35c in Hardy (1943)] ........................................................................... D. cinctus (Banks, 1915)

– Both surstyli slightly sideways-directed [fig. 100 in Rafael (1995)] or clearly sideways-directed (Fig. 34) ............................................................................................................................................ 5

5. Phallic guide with a tuft of small setae dorsally [fig. 101 in Rafael (1995)]; junction of ventral and frontal margin forming an angle of about 110° [fig. 101 in Rafael (1995)]; phallus trifid, with ejaculatory ducts not distinctly separated [fig. 101 in Rafael (1995)] ..................................................... ................................................................................................................ D. nigripedes (Hardy, 1954)

– Phallic guide without tuft of setae dorsally (Fig. 38); junction of ventral and frontal margin of phallic guide curved, not forming an angle (Fig. 38); phallus trifid, with ejaculatory ducts distinctly separated only in distal seventh (Fig. 38) ......................................................................................................... 6

6. Both surstyli thickened basally and medially, thin apically, with outer margins sinuous not forming an angle [fig. 54 in Rafael (1995)]; phallic guide with dorsal margin curved upward in distal half [fig. 54 in Rafael (1995)] ............................................................................ D. eremita (Hardy, 1954)

– Both surstyli with basal half thickened and distal half thin, with outer margin forming an angle (Fig. 34); phallic guide straight, slightly curved upward only in distal third (Fig. 38) ...................... ................................................................................................................... D. nigellus (Rafael, 1991)

7. Both surstyli more thickened medially than basally and apically, with inner margins sinuous (Fig. 47); phallic guide with upper margin straight and a tuft of small setae basally (Fig. 51) .......... .................................................................................................................. D. santainesensis sp. nov.

– Both surstyli thickened basally and medially, thin apically, with inner margins straight and outer margins curved (Figs 8, 21); phallic guide with upper margin sinuous and a tuft of small setae centrally (Fig. 12) or with stout and rigid lobe dorsally (Fig. 25) ................................................................... 8

8. Both surstyli with acute apex (Fig 8); phallic guide with upper margins sinuous and a tuft of small setae centrally (Fig. 12); phallus trifid with ejaculatory ducts distinctly separated only in distal quarter ......................................................................................................... D. colombiensis sp. nov.

– Left surstylus with rounded apex, right surstylus with truncated apex (Fig. 21); phallic guide with a stout and rigid lobe dorsally (Fig. 25); phallus trifid with ejaculatory ducts distinctly separated only in distal ninths ........................................................................................................ D. gibber sp. nov.