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Asilidae (assassin flies, robber flies; order Diptera, suborder Brachycera) Family of medium to large, elongate, bristly flies, which have a horny proboscis adapted for piercing. The legs are powerful and flexible, with large pulvilli, and a bristle-like empodium. A prominent tuft of hairs, or ‘beard’, and protruding eyes are also characteristic of the asilids. Virtually all adults are predators of other insects, using their long legs to grasp and carry off prey. The proboscis, used to pierce the prey and suck it dry, can easily enter the hardest of cuticles, and in certain cases may inject venom. Asilid larvae are either predators or scavengers in soil, leaf-litter, or other ground substrates. Larvae are amphipneustic; their mouthparts comprise a hook-shaped labrum, sharp mandibles, and broad maxillae with two-segmented palps. The Asilidae is the largest family of Brachycera, and contains at least 4000 described species.