Scorpion fly overview
Scorpion flies got their name because the tail end of the adult male's abdomen is swollen and turns up to look like a scorpion (see the photographs and drawing below), but the insect is harmless. The swelling is actually the genital capsule. The female (right) is similar, but with a slim, straight abdomen. Both have the beautiful wing pattern seen in the photograph below.
The adults are scavengers feeding on dead insects, rotting fruit, and even bird droppings. They prefer shady locations, and as they are weak fliers they tend to crawl about on vegetation. Although they are not common insects the shape of the head and the tail, if you find a male, makes them easy to recognise.
Scorpion fly life cycle
Eggs are laid in the soil, and the larvae live in the soil where they scavenge in the soil and leaf litter eating vegetation as well as dead insects and invertebrates. The larvae have 3 pairs of thoracic (true) legs and 8 pairs of prolegs, so are caterpillar-like, but they loose their prolegs after the first moult.