>If the "older" larvae are disposed of due to age then I have to ask why is it that emergency queens cells are not desirable for using in making splits as I have read so many times?
I don't know why you've read it so many times...
http://www.bushfarms.com/beesqueenrearing.htm#emergencyqueensquote
"It has been stated by a number of beekeepers who should know better (including myself) that the bees are in such a hurry to rear a queen that they choose larvae too old for best results. later observation has shown the fallacy of this statement and has convinced me that bees do the very best that can be done under existing circumstances.
"The inferior queens caused by using the emergency method is because the bees cannot tear down the tough cells in the old combs lined with cocoons. The result is that the bees fill the worker cells with bee milk floating the larvae out the opening of the cells, then they build a little queen cell pointing downward. The larvae cannot eat the bee milk back in the bottom of the cells with the result that they are not well fed. However, if the colony is strong in bees, are well fed and have new combs, they can rear the best of queens. And please note-- they will never make such a blunder as choosing larvae too old."--Jay Smith, Better Queens
"If it were true, as formerly believed, that queenless bees are in such haste to rear a queen that they will select a larva too old for the purpose, then it would hardly do to wait even nine days. A queen is matured in fifteen days from the time the egg is laid, and is fed throughout her larval lifetime on the same food that is given to a worker-larva during the first three days of its larval existence. So a worker-larva more than three days old, or more than six days from the laying of the egg would be too old for a good queen. If, now, the bees should select a larva more than three days old, the queen would emerge in less than nine days. I think no one has ever known this to occur. Bees do not prefer too old larvae. As a matter of fact bees do not use such poor judgment as to select larvae too old when larvae sufficiently young are present, as I have proven by direct experiment and many observations."--C.C. Miller, Fifty Years Among the Bees