Diptera are characterized by a single pair of wings and usually sucking mouth parts. Many insects that have fly in their name, such as dragonflies, damselflies, fireflies, and mayflies are not flies at all , but belong to different orders.

Flies undergo complete metamorphosis. The larvae do not have wings, and are usually wormlike in appearance. In some species, the larvae are aquatic. The most common examples of Diptera that we find in the ponds in Brazos Bend State Park are mosquito larvae and midge larvae. At certain times of the year, horse fly and soldier fly larvae are also found.

Mosquito larvae are very small, covered with small spines. They are usually about 5 mm long. They have a large head and the thorax is wider than the abdominal segments. They usually swim near the surface of the water. They move about by bending and unbending their bodies, which gives them the name wigglers.

Mosquito larvae are food for fish, and for other aquatic insects.

Mosquito (Culicidae) Larva

Non-biting midge larva – approximately 4 mm long

Non-biting midges make up the family Chironomidae. They are often bright red in color, and are sometimes called bloodworms. The red color is because they are one of the few insects that have hemoglobin in their blood. This means that they can carry oxygen in their blood.

They range in size up to 20 mm long. Their bodies are segmented with a pair of appendages that look like legs at each end. They also have several hairs on their last segment.

Horse fly larvae (family Tabanidae) are common in the ponds of Brazos Bend State Park in early Summer.

They are light colored, about 1 inch long, with no legs. The head is small and has 2 sharp fang-like appendages that can slash downward to cut its prey. It has stumps called proto-legs on each segment of its body that it uses for pushing itself along. They resemble the larvae of soldier flies, but lack the mass of hairs on the last abdominal segment of a soldier fly larva.

Horse fly larvae are predators. They prey principally on aquatic worms, but have been known to attack larger animals.

Horse fly Larva (Tabanidae) 18 mm long

Soldier fly Larva 25 mm long

Adult soldier fly 19 mm long

Soldier fly larvae (family Stratiomyidae) are also found at Brazos Bend State Park. The larva resemble large brown slugs, with a small protruding head, and a mass of hair on the end of its abdomen.

Head of a Soldier fly Larva

Soldier fly larvae feed primarily on algae and decaying plant matter. They live in the mud at the bottom of the pond. They resemble Horse fly larva but do not have the pro-legs, and have the conspicuous mass of hairs on the end of their abdomens.

Mass of hairs on the end of the abdomen of a soldier fly larva. These hairs keep water out of the spiracles that it uses for breathing

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Ephemerata - Mayflies

Water Scavenger Beetle

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