More bud galls on Black Wattle. I have only seen this sort once. I think they might be caused by Asphondylia glabrigerminis. Species is described in P Kolesik, RJ Adair, G Eick (2010) "Six new species of Asphondylia (Diptera:Cecidomyiidae) damaging flower buds and fruit of Australian Acacia (Mimosaceae", Systematic Entomology 35:250–267.
There are some poorly reproduced photos in Adair, R.J., Burgess, T., Serdani, M. and Barber, P. (2009) Fungal associations in Asphondylia (Diptera: Cecidomyiidae) galls from Australia and South Africa: implications for biological control of invasive acacias. Fungal Ecology, 2 (3). pp. 121-134.