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  • Robber Fly - (Efferia spp.)

    Robber Fly - (Efferia spp.)

    One could mistake a Robberfly from the genus Efferia for some kind of strange black-and-white bee.




    Staff Writer (7/20/2016): Robberflies are considered 'hanging thieves' becaue they use their arms to suspend themselves from twigs and branches and steal a meal from unsuspecting flying insects. A passerby like a bee, wasp or other fly don't see them as they roam. If they are spotted and within range, the Robberfly will chase the flying insect, eventually overtaking them. Once caught, the Robberfly uses its legs to hold the prey and carry it to a nearby plant. It then uses its sharp mouth to stab the victim and then suck out the victim's insides.

    They make a loud whirring noise as they fly because they beat their wings so rapidly. The Efferia species male is slightly darker than the female. At the tip of the male's abdomen is black 'bulb' Females do not have this feature; instead they have long needle-like ovipositors, which they use to inject their fertilizes eggs into the soil. It may look like a stinger at first glance, but it is not a stinger. Both genders can be found hanging around in open fields, parks, meadows and other dry areas.

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    Details of the:
    Robber Fly


    Category: Fly or Mosquito
    Common name: Robber Fly
    Scientific Name: Efferia spp.
    Other Names: Robber fly

    Taxonomy:
      Kingdom: Animalia
       Phylum: Arthropoda
        Class: Insecta
         Order: Diptera
          Family: Asilidae
           Genus: Efferia
            Species: spp.

    Size (Adult, Length): 13mm to 19mm (0.51in to 0.75in)

    Identifying Colors: white; black; gray; brown

    Additional Descriptors: flying, buzzing, noisy, fast, shiny, metallic


    North American Reach (Though Not Limited To*): Alabama; Alaska; Arizona; Arkansas; California; Colorado; Connecticut; Delaware; Florida; Georgia; Hawaii; Idaho; Illinois; Indiana; Iowa; Kansas; Kentucky; Louisiana; Maine; Maryland; Massachusetts; Michigan; Minnesota; Mississippi; Missouri; Montana; Nebraska; Nevada; New Hampshire; New Jersey; New Mexico; New York; North Carolina; North Dakota; Ohio; Oklahoma; Oregon; Pennsylvania; Rhode Island; South Carolina; South Dakota; Tennessee; Texas; Utah; Vermont; Virginia; Washington; West Virginia; Wisconsin; Wyoming; Alberta; British Columbia; Manitoba; New Brunswick; Newfoundland and Labrador; Nova Scotia; Ontario; Prince Edward Island; Quebec; Saskatchewan; Mexico


    * Keep in mind that an insect's reach is not limited by lines on a map and therefore may appear in areas/regions/states beyond those listed above.