Cockroach behaviors

[evangelist6589]

Every know and then I come home and find a cockroach on his back. I have not sprayed it so I am not sure what does this to the roach, or perhaps this is normal behavior for the insect. The last one I found he was still alive but on his back. I then sprayed him with black flag and he died. In the past when I have sprayed one he then jumps on his back and jerks around wildly for a minute or two until giving up the ghost. Does anyone know?