Order Diptera encompasses about 20,000 species across North America (not including Mexico). These mostly daytime flyers are a common sight during the long summer days across Tennessee on land and near bodies of water. Flies belong to this order and feature sucking mouthparts as well as a second set of full wings - the latter making them excellent flyers. The dreaded mosquito also belongs to the order and females of the species sport blood-sucking mouthparts. Beyond these two, Crane Flies, Gnats, and Bee Flies also belong to the group.
Common Name: "Black Onion Fly"
Scientific Name: Tritoxa flexa
TAXONOMIC BREAKDOWN: The Taxonomic Breakdown is the scientific way to categorize a partocular insect species from its largest group (Animalia) to its smallest (variable). The Genus and Species categorizations taken together make up the species' scientific name shown above, in this case Tritoxa flexa.
Garden Pest: Known to be destructive of garden plants.
Harmful: Known to be harmful in one way or another.
Nocturnal: Most likely to be spotted during night time hours.
Outdoors: Typically found across the great outdoors.
Pest: Generally considered a pest to humans.
Six-Legged: Six legs are common to this insect.
Small / Tiny: Noticeably small to the naked eye.
Striped / Banded: Noticeable stripes or banding pattern.
Winged: Has wings to hop or fly over distance.
The Black Onion Fly has been identified by site users by the following descriptors:
black   yellow   white   stripes   striped   flying   flight   winged   outdoors   garden   eyes   small   six-legged' pest   harmful
The general likelihood of encountering this insect based on a given month of the year in the state of Tennessee. Generally, the best sighting months are June through August with peak occurring in July.
Below is a representation of the 'smallest-small' and 'largest-large' sizes commonly associated with the Black Onion Fly. Due to monitor differences, sizes may not be exact on your particular screen. Conversions to millimeters are provided for convenience.
0.24 inches (6 mm)
0.47 inches (12 mm)
Below you will find the colors most commonly associated with the Black Onion Fly. Both Primary and Secondary colors are represented in the showcase. Due to monitor differences, colors may not be exact representations.
The Black Onion Fly can be found in the following Tennessee counties:
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