I've never heard of botflies. I was in Belize last September and the only time I had any problem with bugs was at Altun Ha. It was REALLY REALLY hot that day and the bugs there were really bad (maybe they were botflies - we just called them #@#$ bugs!). THey bite like crazy and I thought I would be covered with bites but for some reason, the bites seemed to disappear after an hour or so. Best advice is to bring bug spray and don't leave it in the bus like I did!!!