Ok I read it again and found it. I should have read more closely. But I'm still not impressed.

And I'm not sure I wanna trust a source in which the author has no self-confidence. He goes through and explains a whole page about how it could have evolved, and then he goes to say:

The scenario above is hypothetical; the actual evolution of bombardier beetles probably did not happen exactly like that.
But why did you want to know if I knew what a chromosome was?