It is a ladybug pupa :)

swamp milkweed leaf beetle larva

Since it looks like it has spots on the back, rather just along the sides, it appears to be a ladybug pupa, as suggested by psyc1210. This is the stage of development just before the beetle evolves into an adult beetle. Egg, larvae, pupae, adult....remember? ;-)

It is the larva (grub) of the swamp milkweed beetle. There are several different milkweed insects. I have included the link to bugguide for IDing the swamp milkweed beetle grub. However, if you put milkweed into their subject search, you will be able to explore all the wonderful forms and colors of milkweed insects!
Cheers,
Elisabeth

Here is a link that might be useful: swamp milkweed beetle larva

Meant pupa not larva, and looking at it again, I think it might indeed be a ladybug pupa. You can look at both links and decide for yourself!
-Elisabeth

Here is a link that might be useful: ladybug pupa

I am certainly no expert, but it looks just like the Ladybug pupa I see in my yard.