Return to the Butterfly Garden Forum | Post a Follow-Up

Another anatomy lesson, please

Posted by catherinet z5 (My Page) on
Sat, Sep 10, 11 at 12:19

Could you please tell me where its real eyes are again? I found several of these cute little guys on my spicebush this morning. :)
Also, how many instars do these have and can you tell which instar this is? Will it pupate and eclose still this season? (zone 5).
Thanks a bunch!
spicebush swallowtail cat 2

Follow-Up Postings:

RE: Another anatomy lesson, please

Caterpillars are supposed to have eyes/tiny openings arranged in a semi-circle shape on both sides of their heads, but I'm not sure I've ever seen them. Here's a close-up picture of a gulf frit caterpillar, and maybe the dark areas on the head in the shape of a "C" (backwards on one side) are the eyes?
Image hosted by
Your caterpillar isn't green yet, so it's probably one of the first three instars, and by the yellowy color I think I see - probably the yellow "eyes" showing through - it's probably a third instar cat. Cats have a total of five instars.
I made a picture of what I think is a third instar spicebush swallowtail caterpillar - actually, I've never tried to count instars - which looks like yours -
Image hosted by

RE: Another anatomy lesson, please

Thanks Sherry!

RE: Another anatomy lesson, please

Excellent pictures...both of you!


RE: Another anatomy lesson, please

The stemmata of lep larva (sometimes called simple eyes, or in error lateral ocelli) are located on the head capsule in the approximate location the compound eyes of the adult will be, and they only detect movement. Far too much to go into here, but a ton of research has been done based around them, including how and why they metamorphis into compound eyes.

RE: Another anatomy lesson, please

Those little Spicebush cats are so cute! The first time I saw them, I thought they looked like little polywogs. Such interesting changes they go through during their instars. Those fake eyes are very convincing, even when you know they're fake! Which of course, is the whole point.

I've got 8 chrysalises hanging out in the aquarium tank. They pupated between August 16th and the 29th and aren't showing any sign of emerging yet this year. I have no idea what to expect with these guys.

RE: Another anatomy lesson, please

No expectations is the key to raising Swallowtails! I fed a lot of Pipevine Swallowtail caterpillars early in the season. The last one eclosed a week ago. They eclosed all summer long. Your spicebushes will probably overwinter. I would put the aquarium tank outside on a porch or in an unheated garage. And start checking it again in the spring. I have had SBs eclose as late as October here, but I'm in zone 7.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Butterfly Garden Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here