Stinging Caterpillar from Uruguay is Leucanella viridescens viridior

Subject: Pretty (poisonous?) caterpillar
Location: La Barra, Uruguay
March 7, 2013 2:35 pm
I encountered one of these during my recent trip to Uruguay and was told by the locals to stay away since it’s poisonous. The bright green/yellow color would definitely imply that it doesn’t want me to get too close. Any idea what it is?
Signature: Alex

Automeris Caterpillar
Leucanella viridescens viridior Caterpillar

Dear Alex,
We are nearly certain your caterpillar is a Giant Silkworm Caterpillar in the genus
Automeris, which includes many species of stinging caterpillars including the Caterpillar of the North American Io MothWe will check with Bill Oehlke to see if he can provide a species identification.  We often hear that locals have superstitions about perfectly harmless species being dangerous, including the Black Witch and the Lanternfly or Machaca, but in this case, the locals are right.

Bill Oehlke provides a correction:  Leucanella viridescens viridior
Hi Daniel,
It is Leucanella viridescens viridior, and they can give a nasty sting.
Bill Oehlke

Hi Daniel,
Thanks very much! Glad I didn’t touch it. 🙂

Ed. Note:  Bill Oehlke notes that it is the “Same subfamily Hemileucinae” as Automeris, hence our initial confusion.

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