Also aptly named the Assasin fly, these insects are a large, impressive fly with a nasty reputation.

Robber fly - Zosteria sp. - Photo by Alex Pawlow

They will perch on a rock or branch observing, waiting for a potential victim. When an insect passes, they will launch their attack.

They will take on almost any insect, even ones slightly larger than themselves, which they can catch in flight, with their strong legs. Once they have hold, they set about injecting a powerful neurotoxin with their proboscis / mouth parts. This immobilises their victim, usually killing it almost instantly. It also liquifies the insects insides. They will then carry the insect to a resting place where they can devour them at leasure, sucking their insides out.

They have also been known to take spiders, whilst they are in the process of building their webs.