What a cool find. There must be some Flat-topped Aster somewhere near you because these butterflies only exist near their host plants. These caterpillars will overwinter, which can be tricky because there is a high risk of them drying out. (I tried to overwinter a few one year--failed and didn't want to try it again because I didn't want to harm the local populations).

I guess I would encourage you to find the stand of asters somewhere and release most of the caterpillars. They make a web and feed together--hundreds (so you will need a lot of the plant); they stop feeding about August and rest at the base of the plant for the fall/winter. They re-awaken in spring and resume feeding about the time the host plants have re-leafed.

There are resources about rearing overwintering caterpillars. If you search on this site for a Ladobe's posts, he gave a detailed explantation of a technique he used to get most overwintering larvae to survive winter.

Good luck!

Here is a link that might be useful: Overwintering techniques

Here is a link the the thread that includes Ladobe's post--scroll down for it:

Here is a link that might be useful: Ladobe and overwintering technique

Hi
Could I try New England aster or just try to find the stand cause yesterday I went all over my property then both my neighbors and down and up the road and when I collected them at my cabin they were blooming.
Jacob

No, they will only eat Flat-topped Aster which is why they are rare in that they only have local populations around the host plant, and of course, their habitat is disappearing. If you really have a Harris', there has got to be some Flat-topped around. I can post a pic of my plant later to help with ID.

Do you think you might have some other kind of butterfly that uses asters like a Pearl Crescentspot?

Can you take a photo to help confirm ID?

Hi
I know for sure they are Harris checkerspots because the color of the eggs they are yellow and the pictures of Harris checkerspots look exactly like the live females I have. I don't know how to put pictures on here.
Jacob

How many females do you have? It might be a good idea to release them so they can find the host plant; otherwise, if you keep all the eggs, and the caterpillars don't have enough to eat, the population will be impacted. This species is in severe decline.

I wish we were in the same state--I would love to take some of the eggs. I have a huge plant.

I'm going to be in Illinois in August if you want some?
Jacob