Notch-horned Cleg

Often called the Common Cleg or the Notch-horned Cleg, this is the silent ninja of the fly world. Unlike the loud buzzing of a typical housefly or bumblebee, Haematopota pluvialis is famous for its stealthy approach, often landing unnoticed until it delivers a sharp, startling bite. Its name, "pluvialis," refers to its habit of being most active and "biting-ready" during the humid, heavy air just before a rainstorm.

🔍 How to Identify

• ✈️ Mottled Wings: The most striking feature is the wings, which are not clear but covered in a complex, smoky-grey lace pattern or "marbling."
• 🌈 Psychedelic Eyes: They possess large, stunning compound eyes that shimmer with horizontal iridescent bands of purple, green, and gold.
• 📏 Slender Profile: Compared to the bulky common horse fly, the Cleg is narrower and more elongated, usually measuring about 8–11mm in length.

🌲 Habitat & Ecology

• 💧 Moisture Seekers: You will most likely encounter them in damp meadows, edge-of-woods, and near marshy ground where their larvae develop in wet soil or mud.
• 🌸 Dual Lifestyles: Only the females are blood-feeders; they require a protein meal to develop their eggs. The males are perfectly gentle vegetarians that spend their days sipping nectar from wild flowers like umbellifers.
• ☁️ Weather Sensitive: They are highly atmospheric insects. On hot, thundery days with high humidity, their activity peaks, leading to their reputation as "weather prophets" in European folklore.

⚠️ Safety & Toxicity

• 🩸 Painful Biter: While not venomous, the female uses scissor-like mouthparts to "slash" the skin rather than pierce it. This results in a bite that is disproportionately painful for the fly's size.
• 🩹 Skin Reaction: Bites often result in itchy, red wheals. Because they can carry bacteria on their mouthparts, it is important to clean the bite area to prevent secondary infection.
• 🐕 Pet Awareness: They can be a major nuisance to horses and dogs in rural areas; using pet-safe fly repellents during "muggy" weather can help keep them at bay.

✨ Fun Fact

The Cleg is a master of stealth because it lacks the "pulsing" flight sound of other flies. It has evolved to land so lightly that it can settle on a human arm or a horse’s flank without triggering the tiny sensory hairs on the skin, allowing it to begin its meal completely undetected.