Thermoregulation in bees is one of the biggest, if not the biggest limiting factor in flight performance. Bumblebee thoraxes tend to run at about 35 C to 40 C (95 F to 104 F) during flight, even at low air temperatures. The Argonne National Lab's synchrotron was used to x-ray a few beetles, and provided clear evidence that at least these beetles, if not all insects "breathe". (This was one of the most expensive x-rays ever made, and worse yet, was not covered by any medical insurance policy.) They expel air from their trachea, and the relaxation after the "exhalation" draws air back into the trachea. Backwards from how mammals breathe. Yes, in Saturday's Washington Post, of all places. I guess they wanted to run at least one story that was not about Darth Vader^H^H^H^H^H^H^H^H^H^H^H^H^HGeorge Bush and Iraq. Here's the online version of the article: http://www.washingtonpost.com/wp-dyn/articles/A35267-2003Jan23.html jim