There are around 300 described species of Nemestrinidae, or Tangle-veined Flies, world-wide. They are mainly Gondwanan in distribution. Most are large to medium-sized, compactly built flies with hairy bodies and a complicated wing venation.

Trichophthalma is a large genus within the family that contains 60 or so species. At least 5 of these species occur in Girraween National Park. Most Trichophthalma feed on spring flowers such as Leptospermum Tea Trees. They can be found hovering motionless over open sunny patches – darting away when disturbed, but usually returning quickly to the same spot. All Trichophthalma have parasitic larvae, which probably feed on scarab beetle larvae in the soil.