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Robber Fly

pegesimallus pulchriventris


Also known as assassin fles, this bristley, well built member of the Asilidae has been stalking our garden over the last 2 weeks. Flight is brief and upon disturbance has a 'bobbing' nature that ends with characteristic abdominal contractions apon landing. It favours slower moving prey in flight such as crane flies and bees. The body is 'stocky' with a greatly compressed thorax that ends in a defined hump higher than the head. The legs are long compared to body length and curl inwards at the first join and outwards again towards the end. This leads to the insect standing tall and in a 'ready position' to pursue prey. The eyes are large and very reactive to movement and light. At times, my lens reflected light onto leaves and the insects head would turn very quickly to ascess and then return to forward position. Eggs are laid directly into soil after male and female mate usually on the wing.


Robber flies excel in Subtropical forest margins and long grass beneath trees where high to mid level ambush positions can be found in the path of flying prey.


Very stable subject to photograph and was confortable with close up photography directly in front. Skittish on vegetative movment or a shadow falling on it.

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Michael Strydom
Michael Strydom 2 years ago

Thanks so much Maria ! I know their legs a way longer than ive seen in the past. When they fly they almost look like wasps when their long legs dangle. Even a bit creepy when the hold them horizontal as they bob and weeve.

Maria dB
Maria dB 2 years ago

Really like the third photo - their legs look so much longer than the robber flies I see in my area (or the insects just rarely stand up tall on their legs so I don't see them like this). Very nice spotting!

Michael Strydom
Michael Strydom 2 years ago

Thanks for the nomination Daniele!

DanielePralong 2 years ago

Your spotting has been nominated for the Spotting of the Week. The winner will be chosen by the Project Noah Rangers based on a combination of factors including: uniqueness of the shot, status of the organism (for example, rare or endangered), quality of the information provided in the habitat and description sections. There is a subjective element, of course; the spotting with the highest number of Ranger votes is chosen. Congratulations on being nominated Michael!

Michael Strydom
Michael Strydom 2 years ago

Hi Daniele. Thank you. We are thankfully getting rains right into summer here so nice and humid for bugs. Best christmas present for the cape :)

DanielePralong 2 years ago

Great shots and description Michael!

Michael Strydom
Michael Strydom 2 years ago

Hi Neil. Many thanks for the kind words. Chased him round for a while and finaly got him in the sun :)

Neil Ross
Neil Ross 2 years ago

Oh wow! That's an amazing photo series, Michael. Great spotting, and cheers for the notes.

Michael Strydom
Spotted by
Michael Strydom

Cape Town, Western Cape, South Africa

Spotted on Dec 17, 2018
Submitted on Dec 17, 2018

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