robber fly

American  

noun

1. any of numerous swift-flying, often large, dipterous insects of the family Asilidae that are predaceous on other insects.

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robber fly British  

noun

1. Also called: bee killer.   assassin fly.  any of the predatory dipterous flies constituting the family Asilidae , which have a strong bristly body with piercing mouthparts and which prey on other insects

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Etymology

Origin of robber fly

First recorded in 1870–75

Example Sentences

But they think that the robber fly may get a second advantage from its resemblance to the bumblebee.

From Time Magazine Archive

The robber fly even has bunches of light hair on its hind legs to resemble the baskets of pollen that the bumblebee usually carries.

From Time Magazine Archive

The big difference between the two: the bee can sting and the robber fly cannot.

From Time Magazine Archive

Instead of working with butterflies, the Drs. Brower selected two insects, the bumblebee and the robber fly, that are very distantly related but look very much alike.

From Time Magazine Archive

Now, instead of hatching a butterfly, out comes this robber fly, a long, lean, sleek-looking fellow that has been living for weeks on the body of that poor caterpillar, and we didn't know it.

From Buffalo Roost by Cheley, F. H.