bumble bee mimic robber fly

(Laphria posticata)

Conservation Status

IUCN Red List

not yet assessed

bumble bee mimic robber fly (Laphria posticata)


NNR - Unranked


not listed




June through August


Woodlands and woodland edges


Total Length: ½ to 11 16

          Photo by Luciearl

This is a small to medium-sized, robust, robber fly. The thorax and abdomen are partially covered with long yellow hairs making it resemble a bumble bee. It is thought to be a mimic of golden northern bumble bee (Bombus fervidus). Adults are ½ to 11 16 long

The thorax is stout, black, and evenly covered with long yellow hairs. There is a tuft of black hairs in front of the wings and a tuft of mostly yellow hairs with a few black hairs in front of the balancing organs (halteres). The hairs on exoskeletal plate between the abdomen and the thorax (scutellum) are black.

On the male, abdominal segment (tergite) 1 is entirely covered with black hairs; tergite 2 has a patch of yellow hairs on the trailing edge (posterior) at each side of the upper surface (dorsolateral); tergite 3 has a similar but larger patch; tergite 4 is completely covered with yellow hairs; tergite 5 is covered by yellow hairs except for the forward (anterior) middle part, which has black hairs; tergites 6 and 7 are entirely covered with black hairs. The female is similar except tergites 1 and 2 are entirely black, and only tergite 3 has yellow dorsolateral patches.

There are two large compound eyes and three small simple eyes (ocelli). The compound eyes extend above the level of the top of the head (vertex), making the head appear hollowed out between the eyes when viewed from the front. The ocelli are arranged in a triangle on a prominent rounded projection (tubercle) in the middle of the head between the compound eyes. The upper face has long, yellow, erect hairs. There is a cluster of forward-directed bristles (a “beard”) on the lower part of the face. The beard on males is entirely yellow. On females there are yellow hairs at the upper margin of the beard, black hairs below. The hairs below the sucking mouth part (proboscis) are yellow on the male, black on the female. The antennae have 3 segments. The third segment is elongated.

The legs are stout and spiny. On the male, the third segment (femur) of the hind leg has a weak line of yellow hairs above (dorsally) and below (ventrally). On the female these are all black. The fourth segment (tibia) of the front and middle legs are covered with long hairs. On the female, these are all black. On the male, the hairs on the front (anterior) side are black, those on the back (posterior) side are yellow. On the female they are all black. The hind tibia of both sexes have all black hairs.

The last segment of the foot (tarsus) has 2 pads.

The above description refers to the nominate subspecies L. p. posticata. The other subspecies that may be found in Minnesota is L. p. scutellaris. It has yellow or golden-yellow hairs on the margin of the scutellum and on the upper surface of the hind tibia. Tergite 6 is covered with yellow hairs.



Larval Food


Adult Food

Flying insects, including bees, wasps, beetles, and other robber flies

Life Cycle




Distribution Distribution Map  

Sources: 24, 27, 29, 30.


No Common Name
Few of the North American Laphria species have a common name. The common name for the genus is bee-like robber fly. Laphria sacrator is one of several species famous for being a bumble bee mimic, so “bumble bee mimic robber fly” will stand in for the common name.



Diptera (gnats, mosquitoes, true flies)



Brachycera (circular-seamed flies, mouches muscoïdes, muscoid flies, short-horned flies)









Asilidae (robber flies)







Subordinate Taxa

bumble bee mimic robber fly (Laphria posticata posticata)


Bombomima brunnea

Bombomima scutellaris


no common name








On insects and arachnids, the third, largest, most robust segment of the leg, coming immediately before the tibia. On humans, the thigh bone.



In flies: a pair of knob-like structures on the thorax representing hind wings that are used for balance.



Simple eye; an eye with a single lens. Plural: ocelli.



The protruding, tubular mouthpart of a sucking insect.



The exoskeletal plate covering the rearward (posterior) part of the middle segment of the thorax in some insects. In Coleoptera, Hemiptera, and Homoptera, the dorsal, often triangular plate behind the pronotum and between the bases of the front wings. In Diptera, the exoskeletal plate between the abdomen and the thorax.


Tergum; tergite

The upper (dorsal), hardened plate on a segment of the thorax or abdomen of an arthropod. Plural: terga.



The last two to five subdivisions of an insect’s leg, attached to the tibia; the foot. Plural: tarsi.



The fourth segment of an insect leg, after the femur and before the tarsus (foot).



The upper surface of an insect’s head.






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Robber Fly having a meal

  bumble bee mimic robber fly (Laphria posticata)    
MinnesotaSeasons.com Photos



  Laphria posticata
Steve Collins
  Laphria posticata  



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Location: Cass County

Robber Fly having a meal

bumble bee mimic robber fly (Laphria posticata)

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