Jim,

I see what you mean. I was thinking that I need to have the feedback from
the drone pupae itself. I guess you are right, one can figure out a
correlation between the actual brood temp and the the bi-metal thermostat
and perhaps fiddle with thickness of the wire on the bi-metal (in case that
it shuts off before the drone pupae are cooked or, conversely, too late) --
providing that the bi-metal can be custom-made perhaps.

perhaps there could even be sensors that "read" out how much brood is
already sealed inside the hive on this frame. I remember Tom Webster used to
have a royal jelly monitor inside queen cells that can assess the quantity
of food with some electric terminals...

Zachary
http://www.mitezapper.com