Tag Archive | Chelifer cancroides



What could this little creature be?  I found it crawling across a ceiling.  Looks like a tick, maybe, or some minute crab.  It is about one-quarter inch long and a fast mover.

Over the years I’ve found several of these in my house, mostly in the library.  I’m sorry to say I killed the first few, before a friend told me what they are.  Pseudoscorpions.  The one pictured is likely a house pseudoscorpion, Chelifer cancroides.  They are members of the spider family.p1

These tiny, alert insects are quite beneficial in the home because they eat various insect pests including mites, springtails, ants, beetle larvae and book lice.  Hence their appearance on our book shelves.  They like humid areas with wood, probably because their prey prefer these places.

Pseudoscorpions are not a danger to humans.  They do have venom, in their large front pincer appendages, but they are too small to pierce our skin.  These spiders are known to hitch rides on larger animals to travel around.

Their lives are quite interesting.  The adults do not have sex in the way we understand.  The male deposits a semen packet in an area he specially prepares then waits until a female is attracted by his sexy scent.  When she arrives, he does a mating dance then guides her to the semen packet where she takes it into her body to fertilize the eggs.  The eggs brood in the mother and the nymphs sometimes ride on her back after they hatch.  The babies go through three molts before reaching adulthood.  The insect’s lifespan is 4-5 years.

Now that I know what these little guys are doing, I welcome them in our book-filled house.  They are performing quite a service for us.