> In respect of Garth Cambray's comment on the bees liking the extra space
> in the lid so that mats may be a bad idea, perhaps this is the reason of
> ensuring there is a margin of space so bees can move into the lid.  I
> assume they sometimes use the lid to draw cooler air through the hive as
> sometimes I lift the lid and find a mass of bees on top of the hive mat.
 
I assume then, that the hive mats of which you speak are smaller than the
inside of the top of the super?
 
What then  are the dimensions of the supers you use and the mats?
 
Allen