Stinging Flannel Moth Caterpillar from Mexico

Venomous Mexican Stinging Caterpillar
Sun, Feb 15, 2009 at 9:29 AM
I am wondering if anyone knows what sort of caterpillar this might be? It was about 1″ long, a creamy light green color, and was covered with very long dark brown hairs. It was originally much fatter than shown in the photo – by the time the photo was taken, it had dehydrated a bit due to being carrying around in a plastic bag trying to get it identified. Unfortunately I just had a very nasty encounter with one of these, in in the Yucatan peninsula of Mexico (Isla Mujeres – just off the coast by Cancun). It dropped out of a tree and stung me on the leg. It immediately felt like the burn of a bee sting but rapidly progressed beyond this. Caused a large welt and redness and swelling of sting area about 6″ around. But the worst part was the systemic effects of the sting which were horrible (incredible back muscle spasms, tremendous abdominal pain, and intense nausea) such that I ended up in the emergency room. Have looked on the internet to try to find out what it was, but have also been unsuccessful in determining this. Even the locals there couldn’t tell us although most knew that it was very painful and to be avoided at all costs. Any entomologists out there looking for a challenge??? Would sure love to know what this nasty little bug was…
Isla Mujeres, Quintana Roo, Mexico (Yucatan Peninsula)

Unknown Stinging Caterpillar
Flannel Moth Caterpillar

Hi Yvonne,
We haven’t the time to research this at the moment, but perhaps a reader can provide the answer. We don’t believe this is a Stinging Slug Caterpillar in the family Limacodidae because they don’t generally have hair. We really hope to properly identify this specimen for you and add your public service message to our archives.

Update: Eric Eaton contacted Doug Yanega who provided the following ID:
Tuesday, February 17, 2009
That’s the larva of a Megalopygid, probably a Megalopyge species near
M. lanata
The long hairs are not the stinging hairs; the stinging hairs are
short, arranged along the side of the body not far above the prolegs.
Doug Yanega
Dept. of Entomology
Entomology Research Museum
Univ. of California, Riverside, CA

I was curious, so I asked around.
could use an identification and maybe some warnings, given that Spring Break is about to happen. The critter looks pretty tame, actually, not spiny like you tend to associate with venomous ‘pillars.
Please credit Doug with this. Thanks. Eric.

Ed. Note: Moths in the family Megalopygidae are known as Flannel Moths and the Caterpillars are sometimes called Asps because of the sting, or Puss Caterpillars.

Tuesday, February 17, 2009
Hi Daniel:
This looks like the caterpillar of the Flannel Moth Megalopyge lanata (family Megalopygidae). It has appeared on WTB before (Unknown Panamanian Caterpillar on Cashew Tree – April 5th, 2008) and a lot of good information was given in response to that post. It is widespread throughout Central and South America and is definitely a creature to be wary of. Regards.

Thanks for the info! Indeed, the photo noted below is a dead ringer for the
guy that stung me.
I have put a link to your website on an information site for the island,
just so that others can be aware and give a wide berth to this nasty little
Thanks for all your help
Yvonne Hillsden

Friday, , February 20, 2009, 3:21 PM
Saw the post about the stinging caterpillar earlier in the week. the systemic symptoms sounded familiar to something I had come across recently. You may or may not want to share the attached pdf (cmaj-death-from-caterpillar ) with Ms. Hillsden.
Jeffrey B. Tucker, B.C. E.
Entomology Associates, Inc.
Houston, Texas

Update: Sun, Feb 22, 2009 at 10:07 AM
Hi Daniel,
Thanks for the heads up.  I had read the CMAJ article already (just after I had been stung actually) and frankly it had scared the crap out of me!  That was one of the reasons why I was so anxious to have my particular culprit identified.  I was very relieved when the entomologist from CA identified my guy as a flannel/puss moth sp.  Would definitely not have been happy to hear that it was a type of lonomia!
Who’d ever think these cute little furry guys could pack such a nasty punch!

7 thoughts on “Stinging Flannel Moth Caterpillar from Mexico”

  1. just encountered a flannel moth catepillar in my wife’s bed at 3 am. I picked it up with a kleenex, but it stung through the kleenex. Then used a paper towel and hammered it with a shoe. still did not kill or even squash it. its now in a jar and moving a little slower. We are in Lake chapala area near juadalahara Jalisco mx. got a red spot when the spines pricked me and minor discomfort but no other systems yet…..Jan 15 2016…….wife can’t get to sleep now! moved to my bed!

  2. Ugh, great… I’m leaving for Isla Mujeres in six days. I’m glad to know about this in advance but also not looking forward to my trip as much. 🙁

  3. Got bitten yesterday …tried every household chemical and medicine to ease pain…mosquito repellant mixed with colgate mint winter green toothpaste and loads of ice works wonders and four benadryl capsules take two first and two after two hours


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