Boxelder and Milkweed bugs

I thought these were the same bug until I looked more closely. One feeds on milkweed seeds, the other on boxelder or maple seeds. I usually notice them late summer and there's still a few kicking around.

These are the milkweed bugs:

Here's a shot of one of the nymphs moulting out of its old exoskeleton:

Now here's the boxelder bugs:

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