Fly (Robber Common) Neoitamus melanopogon
Scientific name: Neoitamus melanopogon
Common name: Common Robber Fly, Assassin fly, Bee killers.
There are more than 7000 species of robber fly worldwide. New Zealand's specimens are large up to 23mm long. and are common in forest clearings in the North and South Islands.
They have bristles on their legs and their eyes are wide apart giving them excellent 3D vision.
This fly has a bright yellow structure underneath each wing called a haltere, a reduced hindwing which stabilises the robber fly in flight. These halteres operate as vibrating structure gyroscopes.
They perch on vegetation before dashing out to grab prey. They will take anything from ants to butterflies even bees. Notice their large claws that they use to hold onto the insects they attack by diving onto the backs of flying insects where they bite the soft part of their neck paralysing them by injecting a neurotoxin. This is followed by digestive enzymes which liquefy the internal organs. The fly then sucks out the insides of their victim. They lay their eggs in soil or on plants. The maggots live in the soil or rotting vegetation.
A male robber fly has large and bulbous gentialia at the end of the abdomen. – females have a tapered/pointed back end to the abdomen..
Male Notice the halteres ( the knobbed stalks) on the fly just behind the wings.
The large claws of the robber fly