If you venture from Merida to archaelogical sites in the spring, be sure to apply insect repellent to avoid chigger attacks.  These tiny insects jump from grasses and plants and are able to penetrate socks. 

If you are attacked by chiggers, the bites may swell into welts, causing much discomfort.  Slices of heavily salted limes work as a natural poultice and offers much relief.