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Collected this Tachinid fly (I think) on a farm in Still bay, Western Cape, South Africa two days ago (close to sea level, 5km from the ocean). The fly was found on a wild flower at the time. I would like to confirm the genus and progress the ID if possible...

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Clearly a Gonia. I am not familiar with your fauna, might very well be G. bimaculata (very widespread Palaearctic and Afrotropical region)

Theo

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Excellent, Thanks Theo.

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Crosskey (1984) writes of Afrotropical Gonia: "Two species, but names possibly synonymous. Gonia rubriventris Macquart, known only from ♀ holotype (BMNH), South Africa, perhaps not distinct from the widespread G. bimaculata Wiedemann. Holotype of rubriventris has black abdominal colour confined to a single posteromedian spot on T3 and T4 and to the apical half of T5, whereas ♀ of bimaculata usually has at least whole posterior half of T4 and all of T5 black. No specimens agreeing exactly with abdominal colouring of rubriventris have been seen amongst long series of bimaculata examined and rubriventris maintained as valid pending further evidence."

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If it is only one female based on these features, you can forget about it. Highly unreliable, as least in Palaearctic species, as already known since the days of Mesnil’s in Lindner (Die Fliegen…) revision.


Theo