This morning next to the bathroom sink I spotted what at first glance appeared to be a tick with unusually long front legs. I took a closer look, and was overjoyed to see that it was in fact a pseudoscorpion–a little beast I’ve been wanting to see in person for a long time.


Pseudoscorpions constitute their own order of arachnids, Pseudoscorpiones. A quick look through the photos on BugGuide gives me the impression that they all look about like this, but I suppose mine is most likely to be the cosmopolitan house pseudoscorpion, Chelifer cancroides. A photo session with this crazy little thing (~2.2 mm long) clearly took priority over breakfast, so I brought it straight down to my desk to see what I could do with it.

IMG_6694 IMG_6696 IMG_6701 IMG_6714 IMG_6719 IMG_6723

I’m curious about that little nubbin in the back–I don’t see it in the other pseudoscorpion photos I’ve browsed through. I tried to flip it over and get some ventral shots, but it wasn’t interested in lying on its back. As it turns out, a close-up ventral view is needed even to identify these to suborder. Maybe I’ll bump into it again and try harder to get those shots next time; after the photo shoot I set it free on a house plant to join the crab spider that has been devouring the aphids there, if it so chooses.

Now that I’ve finally seen a pseudoscorpion, my new ambition is to find one hitching a ride on a fly.

About Charley Eiseman

I am a freelance naturalist, endlessly fascinated by the interconnections of all the living and nonliving things around me. I am the lead author of Tracks & Sign of Insects and Other Invertebrates (Stackpole Books, 2010), and continue to collect photographs and information on this subject. These days I am especially drawn to galls, leaf mines, and other plant-insect interactions.
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18 Responses to Pseudoscorpion

  1. Iris Clearwater says:

    Wow, Charley, blowing my mind a-gain! Thank you !!!

    *Growing Healthy Communities within Healthy Communities*

  2. Nancy Braker says:

    Thank you for the very awesome photos! Your information is great too and much appreciated.

  3. Moni says:

    Have also found them running around our house. They are cool critters! Did not know about them hitching rides! Now, to find one doing so!!
    Thanks also for the tip to photograph the ventral side for ID…have not done that, so will not post them. Perhaps the next one I see.?

  4. Jesse Poutasse says:

    Regarding the nubbin, might it be a mite? It’s been a long time since I’ve seen a pseudoscorpion. Nice depth in the photos.

  5. daidunno says:

    Look under bark near where you found this one and you’ll probably find more.

  6. David McIntyre says:

    I took apart a small chicken coop once, and I found one or more pseudoscorpions just about every place two pieces of wood met. I’ve been wondering since then whether I could create a pseudoscorpion trap (a trap-and-admire trap, not trap-and-exterminate trap, of course), and precisely which features of the chicken coop made it so appealing to them. Would it suffice just to screw two pieces of wood together and leave them out in the yard, or is the presence of chickens essential? Perhaps one of these days I’ll actually get around to experimenting a bit.

  7. Charley, congratulation for your work. I’m fun of you! Pseudoscorpions are used also for the varroa mites in beehives. Visit:
    Best wishes from Greece MinoanBee

  8. Jane Winn says:

    Great photos! For the ventral side – how about photographing through glass. The pseudoscorpion can be right-side up, and you can be up-side down. – Jane

  9. Anonymous says:

    Hi Charley,

    Great photos of such a very cool species.

    Are you familiar with these cocoons? Wood boring moth of some sort? (opened and eaten by gray squirrel) (partially opened by squirrel)

    • They look like beetle pupal cases to me. I don’t have a copy of my book handy, but it includes a photo of some pupal cases made by a particular genus of scarab that I think are pretty similar.

  10. Anonymous says:

    Okay Charley. Pg. 246 you have a picture of a similar structure, but located on a hop hornbeam tree or a similar looking tree and constructed using the same tree.

    I guess using different tree/wood material I could see these being the same structure. I actually took the empty one home because I thought it was pretty cool. Very sturdy cocoon/case. Thanks for the help.

  11. This is great! I’ve seen only one pseudoscorpion, unfortunately already dead in a dish of aquatic macros. Quite the unexpected surprise! Some of the photos I took of it are here in a newsletter by the Vermont Entomological Society, along with general pseudoscorpion info:

    Click to access VES%20News%20-%20Fall%202009.pdf

  12. Trish Dunbar says:

    I found this little guy, upside down & alive, in tbe egg holder in my fridge (!!??). Trying to find out what he could be, I found your website & found your pictures of the pseudoscorpion – similar but not exactly the same. I have a couple of pictures, taken with my cell phone & using a jewellers loop as a magnifier (strange but it worked) but can’t upload them here. I’ll send the best one(s) if you’d like them. I live in the central interior of British Columbia.

  13. Pingback: The Mini Scorpion | theCraftyKatydid

  14. Annie G says:

    I’m thrilled was thrilled to discover your blog this morning as I searched the internet for an I.D. of the pseudoscorpion that I just found in my bedroom….and so, I imagine, is the pseudoscorpion who has been released. Your photographs are fantastic.

    Now, can you tell me what the preferred time of day to feed is for raspberry cane borers? I’m trying to catch them before they circumambulate anymore vines.

    • I’ve only once seen an adult raspberry cane borer in the act of chewing punctures around a stem, so I’m not sure, but if you snip off the affected portion as soon as you see it, you will remove the larva and prevent damage to the rest of the cane.

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