A Zelus genus nymph from the Southeastern United States.Adult insects often range from 4 to 40 mm. They most commonly have an elongated head with a distinct narrowed neck, long legs, and a prominent, segmented tube for feeding (rostrum). Most species are dark in color with hues of brown, black, red, or orange. The most distinctive feature of the family is that the tip of the rostrum fits into a groove in the prosternum, where it is rasped against ridges there (a stridulitrum) to produce sound, a tactic often used to intimidate predators.
If harassment continues, they can use their rostrum to deliver a painful bite which in some species can be medically significant.
Assassin Bug (Gminatus australis) They use the long rostrum to inject a lethal saliva that liquefies the insides of the prey, which are then sucked out. The legs of some of these bugs are covered in tiny hairs that serve to make them sticky to hold onto their prey while they feed. The saliva is commonly effective at killing substantially larger prey than the bug itself. As nymphs, some species will cover and camouflage themselves with debris, or the remains of dead prey insects. Some species have been known to feed on cockroaches or bedbugs (in the case of the masked hunter) and are regarded in many locations as beneficial. Some people breed them as pets and for insect control.