Biting and Stinging Pests


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Some species of adult black fly females are fierce biters, whereas others are strictly a nuisance by their presence around one's nostrils, ears, arms, hands, and other exposed skin areas.

At first look, the bite may appear as a small, red, spot surrounded by a slightly reddened, swollen area. Next, the area becomes increasingly itchy, swollen and irritated, sometimes for several days. Some black flies readily attack people, whereas others prefer domestic animals or birds, often feeding during the daylight hours and sometimes into the night. Flies may become abundant and be drawn into the air passages of livestock causing serious illness.

Adult black flies are about 1/8-inch long (2 to 5mm), black gray or even yellow colored, broad clear winged without hairs or scales with heavy veins near the anterior wing, have short 11 segmented antennae, large round eyes (no simple eyes) and the thorax (middle body region) is strongly convex, giving a humpbacked, gnat-like appearance.

Small creamy-white eggs (look triangular) about 1/32-inch long (0.1 to 0.4mm) are deposited on the water surface or attached in compact masses on stones and vegetation in shallow fast-running water ways, streams and rivers. Larvae, black to light brown in color, cylindrical, about 1/4-inch or more long (10 to 15mm), are quite active and abundant, sometimes look moss on rocks and fallen trees near water. Pupa are basket-shaped 1/8-inch long (2 to 5mm) in the water.