<I wonder if anyone is familiar with the construction of the <above device? In german it is called "Baurahmen" and enables <the beekeeper to see activity on the comb without opening the <hive. I will try. Please keep in mind that in parts of Germany and Switzerland old style hives are worked from behind and not from the top as is usual in Langstroth hives. This means: In order to get to the front most frame all others have to be removed first! If you want to check whether your bees are going to swarm or not you have to remove a couple of frames first, rather then lifting a super. In order to avoid this work the last frame is an empty one, called "Baurahmen (building frame)" in German. During swarming time (May and June around here) bees are usually busy filling this empty space with comb, usually drone comb. The theory now goes if the bees are going to swarm they will greatly reduce or stop comb building activity shortly before they leave. Observing this building frame thus will give you an indication what the bees are up to. This stopping of comb building is certainly not a sure sign but good enough for practical purposes. That's why it is popular for beekeepers to use this building frames. In addition it has the advantage that young bees always have an opportunity to build combs which helps in reducing the swarming tendency. In my case I welcome these additional drone combs as an opportunity to get rid of some Varroa mites at the same time. As is well known mature Varroa mites prefer to enter drone cells for mating and egg laying. After the cells are capped I remove the combs, deepfreeze them and recycle the wax. In itself this drone comb removal is not enough to keep a complete check on the mites. However, data gathered clearly shows that it will help reduce the total mite count reached by the end of the season. The wax is of a special quality because it has never come in touch with any alien substance and I keep it for people that want to use it for medical ointments etc. I hope this explanation helped in making clear what this "building frame" is and why it is used. It's an old technique originally used to just monitor bee temper. With the arrival of Varroa mites it has shown advantage in "syphoning off" Varroa mites. My best wishes, good luck and few Varroa problems Hans ____________________________________________________ Hans-Ulrich THOMAS. Beekeeper & collector of books about: - bees and beekeeping - ants (yes these small little buggers!) - nature printing e-mail: [log in to unmask] CompuServe: 100045,2556 Fax: +41 1 633 10 77 ____________________________________________________