Sphinx on mint--that is odd.

I cannot see the head horns on your cat, can you provide an image of that or have you definitely seen them?

Sphinx moth larva pupate on the ground, or even underground.

All the advice I have seen about mint control involves a lot of root digging over several years. That and do not let any plants go to seed.

Thanks for your input, Larry. I took another pic and you are right the horns are missing. I also noted some white things on the side of the caterpillar's head. So, I googled "parasite on caterpillar" and now I think it's a hornworm (I got the Family right, Sphingidae ...just the wrong genus :)....not sure what species but the white things are most likely eggs of parasitic braconid wasp Cotesia congregata. I guess hornworms like Perilla!

This post was edited by adidas on Sat, Sep 20, 14 at 11:51

Yes, that is definitely a sphinx cat.

Google sphinx+moth+mint+host and note there are references to sphinx cats on mints. There are apparently tree-preferring species and herb-preferring species of these moth larvae.

Lintneria eremitus.....the Hermit Sphinx caterpillar. The larvae feed pretty exclusively on members of the Lamiaceae (mints, etc.) family.

Lintneria eremitus.....the Hermit Sphinx caterpillar. The larvae feed pretty exclusively on members of the Lamiaceae (mints, etc.) family.

I can't really tell what the white things are in your image, but they don't appear to be Brachonids. Their eggs are inserted into the caterpillar by the adult wasp and their very visible cocoons form just before the newly formed adult emerges.

I suspect that you are seeing the eggs of Tachinid flies, another important parasitoides of caterpillars (and others) . They tend to attach their eggs to the head area, unlike the Brachonids which insert their eggs along the length of the body.

Thank-you for the ID! That's it! So question is, do I try to remove those eggs? is it too late once they're laid AND most importantly to me....though moths and butterflies are beautiful and the flies that lay those eggs are, well, flies do I really want to interfere? I'm sure the flies are useful in some respect to predators or as predators? What would you do?

Went back to look at caterpillar and wish I hadn't. It was covered in larger white objects and small grub like things were coming out of it. So, I'm confused how do the white things on the head which looked like eggs to me relate to the grubs that were coming out of the caterpillar? Could it have been hit by 2 separate parasites?

rhizo--good call on the typical location of the eggs.
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Some people who rear these moths keep the cats caged/netted up with the appropriate hostplants, just to keep these kinds of parasites away. Laundry hampers with see-through mesh are one low-cost method.

Trying to prevent this out in the open would be nearly impossible.