> I would have run your slanted line much more horizontally through the middle of the
> smaller zigs and zags, rather than through the final point, until we see whether the
>final point is actually part of a trend.

Granted, if it were intended as a trend line, but it is actually the upper bound of an area
which represents an imaginary natural drop calculated by taking a simple integral from
 the beginning point to the end point for comparison to the actual mite deaths recorded. 

If it were a  trend  line, it would also have to be broken at the point where the brood
rearing ceased.  That could be difficult because evidence of emerging brood varied from
hive to hive and my goal here is to examine and the variance, not the means.  That chart
is the _average_ of all six hives and represents what is so often presented.  Unlike
most research I've read,  my interest is actually in all the individual hives and the
exceptions which add up to make that average.

>Re the brood/broodless cut off, does that date refer to when you think all
>the remaining brood had emerged, or the last date of egglaying?

All my data is from examining the drop boards under magnification.  From the nature
of the the debris I was able to infer when brood emergence ended with -- to me --
acceptable certainty. As for egg laying, I have no way to know.  I suppose an infra-red
thermometer might give an indication, but even that would have to be invasive.
The data behind my inferences are in the  multi-colour  table near the bottom of the
summary page. (Above the weather)
http://www.honeybeeworld.com/diary/files/drop.htm

I did not open the hives during the observations except to quickly move a top brood 
chamber (no bees) to the bottom on some hives.  (More details in the full record).

Some of the hives seem to end emergence much earlier than others.  One seemed
broodless beginning October 29 and the last kept going until November 24.  Of 
course this makes the composite chart less revealing than the individual charts 
which are offered on the same page, with much less analysis markup.  That composite
chart conceals the actual goings-on that vary from hive to hive and is as useful for 
real understanding as saying the average height of an adult human is 5 feet.  (See
http://en.wikipedia.org/wiki/Human_height#Average_height_around_the_world).

I apologise for the voluminous record.  "Like Topsy 'it growed' while I wrote."
I've tried to provide a summary page and explanations , but inevitably, the more I
explain, the more there is to read and the less transparent it  becomes .
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