Phil Pellitteri, UW Insect Diagnostic Lab
Revised:  4/27/2004
Item number:  XHT1112

Have you ever found a strange, scorpion-like creature in your home?  Pseudoscorpions are common, but rarely seen.  They are harmless, small (1/16 to 1/8 inch long), tick-shaped critters that have a large pair of pincers, but lack the long tail and stinger of a true scorpion.  Pseudoscorpions are beneficial, because they feed on carpet beetles, ants, mites, small flies and other critters in the home.  They are usually found in small numbers and spend most of their time hunting in closets and other quiet places.  They cannot bite.  There are a number of species that commonly inhabit leaf litter outdoors, but Cheilfer cancroides is the common indoors species that is found worldwide.

Pseudoscorpions can live for two years or more.  They have silk glands that they use to build retreats and cover their eggs.  They prefer humid conditions in homes and are often found in or near the bathroom.  When cornered, they will often walk backwards and raise their pincers in a threatening posture.  If they fall into a sink they may not be able to crawl out.  It is unusual to see more than one or two a month in the average home.

Control:  Control is neither needed nor suggested.  Because pseudoscorpions eat pest insects in the home, it is better to preserve their numbers.  They are harmless to people and pets.  If needed, pseudoscorpions can be captured on sticky traps, such as glue boards, and should respond to indoor residual ant and roach sprays.