Neurigona Rondani

Neurigona Rondani, 1856: 142 . Type species: Musca quadrifasciata Fabricius, 1781: 448 (by original designation).

Saucropus Loew, 1857: 41 . Unjustified new name for Neurigona .

Key to males of the orbicularis -group (modified from Naglis 2003)

1 Postpedicel small and about as wide as pedicel; acrostichal setae present in two rows; 6 pairs of dorsocentral setae; tibia III with 1–2 strong anterodorsal setae in addition to dorsal setae; abdominal sternite 5 with ventral cuticular projection; surstyli generally ochreous-yellow (except N. lopesi sp. nov., that has surstyli yellow only at tip); dorsal lobe of surstyli with U-shaped or cup-like apical appendage; hypandrium with pair of lateral arms......................... N. orbicularis -group … 2

- Without above combination of characters....................................... other species groups of Neurigona

2 Tibia III with strong yellow dorsal seta at middle, with anterodorsal seta at basal 1/4............................... 3

- Tibia III without yellow dorsal seta at middle, generally with two anterodorsal setae near basal 1/5 and 3/5 (except N. yacambo with only basal seta).................................................................................. 4

3 Male hypopygium (Figs 4, 13–19) with long cup-shaped projection on dorsal lobe of surstylus (Fig. 15) [Brazil: Mato Grosso do Sul and São Paulo; Paraguay]........................................................ N. orbicularis Becker

- Male hypopygium (Figs 2, 6–12) with dorsal lobe of surstylus with short, rugose projection at apex, without long cup-shaped projection (Fig. 8) [Brazil: Tocantins and Goiás]............................................... N. lopesi sp. nov .

4 Eyes touching on face or nearly so (distance between eyes narrower than ocellus width)............................. 5

- Eyes distinctly separated on face (distance between eyes at least 2 times ocellus width)............................. 7

5 Tibia III with 1 strong anterodorsal seta at basal 1/4; ventral lobe of surstylus with notch at ventral margin and noticeably bifurcate at apex (Naglis 2003, fig. 12) [Venezuela]........................................... N. yacambo Naglis

- Tibia III with two anterodorsal setae near basal 1/5 and 3/5; ventral lobe of surstylus without notch at ventral margin and not noticeably bifurcate at apex............................................................................. 6

6 Male hypopygium (Figs 20–25): dorsal lobe of surstylus (Fig. 22) elongate, with apical grooves; apicolateral epandrial lobe (Fig. 23) short, with unmodified setae; basolateral epandrial lobe absent; cercus (Fig. 25) with projection at base and elongate, curved seta at middle; hypandrium (Fig. 24) without lateral projections [Brazil: Mato Grosso]....... N. papaveroi sp. nov .

- Male hypopygium (Figs 5, 26–32): dorsal lobe of surstylus (Fig. 28) with projection above, bearing microtrichia at apex and short cup-like appendage below; apicolateral epandrial lobe (Fig. 29) four-branched: one branch bearing two simple setae, one with branched modified seta, one inner delicate branch with several hairs; basolateral epandrial lobe (Fig. 30) bifurcated, dorsal branch thinner; hypandrium (Fig. 31) with two lateral projections and one anterodorsal projection [Brazil: Rio de Janeiro]....................................................................................... N. tingua sp. nov.

7 Ventral lobe of surstylus apically hook-shaped and downcurved, bearing straight, thin apical seta (Naglis 2003, fig. 13); tibia II with 3 posterodorsal setae [Costa Rica]....................................................... N. pitilla Naglis

- Ventral lobe of surstylus apically not hook-shaped, with stout triangular or rectangular tip (Naglis 2003, figs 10, 11); tibia II with 2 or 3 posterodorsal setae.......................................................................... 8

8 Ventral lobe of surstylus with rectangular tip (Naglis 2003, fig. 10); hypandrial arms equal in length; tibia II with 3 posterodorsal setae; first tarsomere II with distinct anterodorsal seta; face with grey pruinosity [Guyana; Peru]..................................................................................................... N. grossicauda Van Duzee

- Ventral lobe of surstylus with triangular tip (Naglis 2003, fig. 11); hypandrium with left arm distinctly longer than right arm; tibia II with 2 posterodorsal setae; first tarsomere II without distinct anterodorsal seta; face with ochreous pruinosity [Costa Rica]............................................................................. N. guanacasta Naglis