Borgmeiermyia brasiliana (fg-taxon #11, ‘feather-face’ #2)

This is a male of the second taxon to exhibit the highly modified antenna-3, shaped like a feather. All specimens of this taxon are between 4-5mm long and so the photographs are of quite low resolution. However, you should be able to see: the distinctive black body with golden dusting pattern; completely orange legs; slightly shaded wing costa; and the deep facial concavity sporting a highly modified antenna-3 – in this specimen it is slightly curly due to removal from alcohol:

The next (terrible!) photos attempt to illustrate the only female in my sample – males are much commoner (24:1). As you can see, the female has the same colouration, dusting pattern and wing venation but it doesn’t have the feathered antenna-3:

I conclude from this that the antennal feature is a sex-specific adaptation possibly to enable males to find females.

I determined this taxon to be Borgmeiermyia brasiliana (Townsend), using Arnaud (1963) & Sehnal (1998). I first got wind of this genus when Googling for tachinid photos online and discovered a photo on a nadsdiptera page.

• Arnaud, P. (1963) A revision of the genus Borgmeiermyia Townsend (Diptera, Tachinidae)
• Sehnal, P. (1998) A new species of Borgmeiermyia Townsend, 1935, from Paraguay (Insecta, Diptera, Tachinidae)