Myioscaptia, Mackerras, 1955

Lessard, Bryan D. & Yeates, David K., 2013, New species of the hairy-eyed horse fly subgenera Scaptia (Myioscaptia) Mackerras, 1955 and Scaptia (Scaptia) Walker, 1850 (Diptera: Tabanidae) from Australia, Zootaxa 3680 (1), pp. 118-129 : 119-121

Subgenus MYIOSCAPTIA Mackerras, 1955

Scaptia Walker 1850 , subgenus Myioscaptia Mackerras, 1955a , fig. 30, p. 496. Type species Pangonia violacea Macquart, 1850 , Australia, by original designation. Daniels (1989, 2011); Fairchild and Mackerras (1977); Mackerras (1955, p. 496, 1960, p. 122).

Genotype: Pangonia violacea Macquart, 1850 , Australia, by original designation of Mackerras (1955, p. 496).

Morphological diagnosis. Small (8–11 mm), rotund, blowfly mimicking species, usually bright metallic green to dull semi-metallic black in appearance, differentiated from the other subgenera of Scaptia by the short rounded and leaf-like palpi, clear wings and abdomen and scutum without distinct markings.

Female. Length 8–11 mm. Frons usually parallel, sometimes only slightly diverging dorsally and ventrally, narrow, slightly raised at centre. Face truncate to moderately bulging above, with depressions at base and sides, occasionally somewhat shining. Antennal scape and pedicel small, equal to width of stout, cylindrical flagellum with eight distinct flagellomeres, without projections. Palpi short, usually less than length of flagellum and less than one third the length of the proboscis shaft, flattened, broad to resemble the blade of a leaf, with a well defined flat bare area. Proboscis relatively small, less than one and a quarter times head height, relatively slender, heavily chitonised, usually with well-developed labella that is usually greater than the width of the proboscis. Scutum metallic or non-metallic, sometimes shining, usually without conspicuous vittae rarely exceeding the transverse suture. Abdomen short and rotund, metallic or non-metallic, sometimes shining, without obvious markings. Wings clear with prominent stigma; cell R 5 narrowed, or closed with a short petiole; cell M 3 open; vein M 1 without inflexion; R 4 angulate, with or without appendix ( Mackerras 1955, 1960). Mackerras (1960, p. 122) described the genitalia as “eight sternite with gonopophyses rounded; cerci rounded apically; lateral arms of furca relatively large, narrowly fused with lateral edge of 9th tergite.

Male. Length 8–10 mm. Eyes holoptic, with upper facets slightly enlarged. Palpi short, slender, cylindrical and blunt, with an obvious apical lateral bare area. Mackerras (1960, p. 122) described the genitalia as “hypopygium with aedeagus unusually long; coxites normal; style hooked and pointed at tip, but not unusually wide, and without strong hairs.

Key to females of Australian species of Scaptia (Myioscaptia)

1. Dark, green to purplish or blackish species, with abdominal tergites metallic or semi-metallic, and usually a strong resemblance to certain blowflies............................................................................... 2

- Light grey to yellowish brown species, with at most apical tergites of abdomen shining............................. 10

2. Thorax and abdomen, including venter, bright metallic green to dark purplish blue.................................. 3

- Scutum more or less covered with tomentum; abdomen usually dark and dull, venter non-metallic..................... 5

3. Scutum black; abdomen with first two tergites orange brown, contrasting with apical black tergites.................................................................................................... ferromontana Daniels, 2011

- Scutum and abdomen concolorous blueish green to purple.................................................... 4

4. Mesonotum with greyish pruinose stripes; anepisternum dull greyish, less metallic; hairs on margin of calyptral fold whitish.................................................................................. violacea (Macquart, 1850)

- Mesonotum otherwise; more brilliantly metallic, anepisternum metallic, shining; hairs on margins of calyptral fold black......................................................................... inopinata Fairchild & Mackerras, 1977

5. A black species; abdominal tergites with apical bands of ashy hairs; legs brownish black. North Queensland............................................................................................ nigrocincta Mackerras, 1960

- Beard and pleural hairs creamy to deep gold; abdomen purplish blue to bronzy green or greenish black, with golden hairs, which are densest towards apex......................................................................... 6

6. Cell R 5 open, or at most closed near wing margin without well-defined petiole; vein R 4 with at most rudimentary appendix; palpi and legs bright yellowish brown.................................................................... 7

- Cell R 5 closed, with well-defined petiole; vein R 4 with strong appendix; palpi and legs brown to dark brown............ 8

7. Palpi long and narrow; basal flagellomeres swollen; abdomen without blueish hues and less hairy overall; legs with coxae hairs mixed black and gold, femora hairs dark brown to black...................................... collessi Lessard sp.n.

- Palpi usually short, wide and rotund, sometimes narrower in northern species; basal flagellomeres cylindrical; abdomen with blueish hues, sometimes dark green to rich purple; leg hairs creamy gold on coxae and predominantly yellow on femora...................................................................................... bancrofti (Austen, 1912)

8. Frons parallel with dark brown and creamy yellow hairs; palpi dark brown, concave laterally, slightly pointed; flagellum reddish brown basally, with terminal three flagellomeres brownish black, sharply contrasting. Eastern Australia............................................................................................ calliphora Mackerras, 1960

- Frons more divergent with entirely dark brown hairs; palpi brown, short and rounded; flagellum more uniform orange to reddish brown. Western Australia.......................................................................... 9

9. Flagellum pale orange to reddish brown; palpi almost flat laterally; scutal vittae usually extending beyond transverse suture; legs dark brown; apical hairs on abdomen relatively dense................................... gibbula (Walker, 1848)

- Flagellum bright orangey brown; palpi with lateral concavity; scutal vittae limited to the front of transverse suture only; legs entirely black; apical hairs on abdomen sparse............................................ lambkinae Lessard sp.n.

10. A uniformly light grey species; scutum and abdomen more or less covered with yellowish cream hair....................................................................................................... muscula English, 1955

- A yellowish brown species; scutum and anterior half of abdomen more or less covered with tomentum and dull golden hairs; posterior half of abdomen shining dark brown to black................................. nigroapicalis Mackerras, 1960