Eastern Hornet Fly

The Eastern Hornet Fly (Spilomyia longicornis) is a large, yellow-and-black, Nearctic flower fly. A convincing wasp mimic. In addition to being a visual mimic, the Eastern Hornet Fly mimics the behavior of wasps as well, wagging its abdomen up and down, flicking its wings, and waving its dark-colored front legs as if they were long antennae. The unusual eye coloration and patterning, dark spots and blotches overlaying a light background, is characteristic of this species and other species in this genus. Larvae are dendrolimnetobionts, obligate rot-hole inhabitants.

Flight season: August and September

Flowers: More often observed perched on leaves at the edge of woods rather than at flowers, however, it is known to visit asters and goldenrods.

Similar species: Spilomyia alcimus, Somula decora, Sphecomyia vittata, and Temnostoma alternans, which are all yellowjacket mimics.

Field notes: There exists a curious intersection here, between language and mimicry, as the species name “longicornis” refers to the Longhorn Beetles. My guess is that Loew, who assigned the name in 1872, had the Locust Borer in mind, a beetle that has a somewhat similar yellow-banding pattern. Expressed in terms of what it is not, the name draws attention to the convergent evolution of mimicry.

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