On May the 18th I purchased a five frame Russian nuc, it was loaded with bees. The following day I introduced them to their new home which was a standard size brood box. Six days later I opened the hive to check its condition, everything was great lots of eggs, brood etc. And I was able to find the queen she was very, very large dark almost black. For the next 4 weeks I tried not to disturb them to much, lifting the cover to see that they were drawing out more comb etc. However one of my Italian hives(they preferred a nearby hollow walnut tree) swarmed and made me panic so I suited up yesterday June 25 and went through all 3 of my hives frame by frame to check for swarm cells etc. While checking the Russian hive I was pleased to see that all looked great, no queen cells of any sort, brood, eggs, drawn comb. However when I found the queen I was shocked to see that I no longer had a beautiful dark Russian, I now had a slightly smaller lovely yellow(obviously productive) Italian queen. With no sign of old supercedure cells how did this happen. The hive has been active growing and appeared normal throughout this 38 day period.