Some time back, I received this good advice:
 
>YOU CAN PULL OFF THE HEAD AND FIRST PAIR OF LEGS IN ONE
> PULL AND WITH A REASONABLE MICROSCOPE OR EVEN A GOOD
> LENS, LOOK DOWN THE THORACIC TRUNK AND SEE THE TWO
> MAIN TRACHEAL TUBES. IF WHITE AND PEARLY, NO TMITES,
> IF CLOUDY AND/OR DARK, YOU HAVE MITES.
 
I've seen dark, and it is really obvious, but what about cloudy?
 
Can the trachea be cloudy - and white?
 
Seems there is a range from perfectly clear to whitish that looks
normal to me.  The whitish ones have a spiral design on them like a
vacuum cleaner (or bee blower) hose and branch.
 
Is the appearance of the tubes something that varies with the age of
the bee?  Or am I seeing low levels or early levels of mites in the
bee when I see some opacity?
 
I realise that this really doesn't matter too much because if the
infestation is that questionable, I am not having to treat.
 
But I'm still curious.
 
Regards
 
Allen
 
W. Allen Dick, Beekeeper                                    VE6CFK
Rural Route One, Swalwell, Alberta  Canada  T0M 1Y0
Honey. Bees, Art, & Futures <http://www.cuug.ab.ca:8001/~dicka>