The masked hunter, Reduvius personatus, is a type of assassin bug (Hemiptera: Reduviidae). It is originally from Europe and accidentally hitchhiked into the United States. It is now common here, particularly in the east and central areas of this country, including Minnesota. It gets its name from the immature masked hunter's curious habit of carrying dust on its body to camouflage itself. They may appear as walking piles of dust and fluff.
An adult masked hunter is more noticeable, being dark brown to black and elongate oval in shape. When full grown, it's about 3/4 inch long with fully developed wings that cover its body. It has a small head, with moderate length antennae and a short, stout beak. An immature masked hunter is similar but smaller and lacks fully developed wings. They are often covered with dust, lint and other debris, giving them a grayish or whitish appearance. Underneath, however, they are dark-colored like adults.
Masked hunters can be found in and around buildings. They typically live outdoors, especially in wooded areas. However, masked hunters are predaceous feeding on a variety of small insects and other arthropods and may venture indoors in search of food. Some food sources for masked hunters include lacewings, sowbugs, earwigs, and bed bugs.
The presence of a masked hunter in a home is accidental and should be considered as just a nuisance. Masked hunters may inflict a painful bite if they are disturbed or someone tries to pick them up, although they do not actually feed on human blood. They do not actively seek to bite people. The bite feels like a bee sting followed by numbness and swelling. Rarely does a masked hunter bite require medical attention. Masked hunters do NOT transmit any disease.
Fortunately in essentially all cases, no more than a few masked hunters are seen in a home. You can easily control these bugs by physically removing them, (e.g. capturing it with tissue paper or trapping it in a jar and releasing it outdoors). You can also remove them with a vacuum cleaner. Be careful when handling masked hunters to avoid accidental bites. If a masked hunter lands on a person, just gently brush it away.
In the unlikely event that large numbers of masked hunters are found, it is probably because other insects are also abundant. To control masked hunters, find and eliminate this food source. Vacuuming or careful use of insecticides may temporarily control these bugs. However, if their food source remains, masked hunters will find these areas again.