Entomology (Study of Bugs)/Unknown bug


Weird worm
Weird worm  
This bug or caterpillar is on my lemon tree and is the weirdest thing I have ever seen.  It's head looks like an alligator.  I am really curious as to what it is.  Can you identify it?

Hi, Holly:

Thanks for including the image with your question, and especially for including the host plant information.

What you have there is the caterpillar of a Giant Swallowtail Butterfly.  It was recently discovered that there are two species, and without geographic location information, I can't tell you which one.  Here is more about them:

http://bugguide.net/node/view/1028443 - Western Giant Swallowtail

http://bugguide.net/node/view/3253 - Eastern Giant Swallowtail

The caterpillars are rarely present in enough numbers to do significant damage to citrus trees, but you can pick them off by hand if they become problematic.

Take care, thanks for your question.



Entomology (Study of Bugs)

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Eric R. Eaton


I answer insect and spider identification questions ONLY. Attach images if possible. No "what bit me?", "what do I feed this bug in captivity?", or science fair project questions please. NO TECHNICAL QUESTIONS ABOUT INSECT PHYSIOLOGY.


Principal author, Kaufman Field Guide to Insects of North America. Professional entomologist employed previously at University of Massachusetts, Chase Studio, Inc., and Cincinnati Zoo; contract work for West Virginia Department of Natural Resources, Smithsonian Institution, and Portland (Oregon) State University.

Author, Kaufman Field Guide to Insects of North America, Missouri Conservationist magazine, Ranger Rick, Birds & Blooms, Timeline (journal of the Ohio Historical Society). I have contributed to several books as well.

Oregon State University, undergraduate major in entomology, did not receive degree.

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One of the top 50 experts in all categories for AllExperts.com, 2009.

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Principal author of the Kaufman Field Guide to Insects of North America, Smithsonian Institution (contract), Cincinnati Zoo (employer), Portland State University (contract), Chase Studio, Inc (employer), Arkansas Museum of Discovery (guest speaker). Currently seeking speaking engagements, leadership roles at nature festivals, workshops, and ecotours.

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