How to Prevent Phorid Flies in Drains

Why Are Phorid Flies Called Humpbacked Flies?

Phorid flies are called humpbacked flies because of their highly distinctive body shape, the thorax is prominently arched.

Physical Features

• Viewed from the side, the back arches high like a hump.
• The head is tucked under the thorax, giving a head-down, back-high posture.
• Very small, 1–2 mm.
• Dark brown or black.

Origin of the Name

• "Humpbacked", describes the arched thorax.
• "Fly", they belong to the fly family.
• "Phorid", from the scientific family name Phoridae; their behavior somewhat resembles fleas in that they can jump or scuttle quickly.

How to Observe?

• Use a magnifying glass or look closely up close.
• The side view is clearest, the distinctive humped profile is obvious.
• This is an important feature for distinguishing them from other tiny flies.

How They Differ from Fruit Flies in Appearance

• Phorid flies: Arched thorax, dark brown, eyes not prominent.
• Fruit flies: Rounder, flatter body, light tan, red eyes very noticeable.

Key Takeaway

If you see a tiny fly with a humpbacked profile from the side, it is almost certainly a phorid fly.