Nothing you can do i'm afraid.
I live next to a field and they get everywhere!!
I found that once they die, after a little while you can tap and wiggle the screen against the desk and they just drop to the bottom.
I was luring it upwards with white part of Firefox window behind it and black part in front when it suddenly just disappeared.
No idea where its gone, but glad it has!
it's gone to reproduce, now you are the proud owner of 100 screen bugs![]()