Yucatan Before and After the Conquest, by Diego de Landa, tr. William Gates, , at sacred-texts.com
The diversity of snakes or serpents is great, of many colors and not harmful, except for two kinds of very poisonous ones, much larger than those we have here in Spain; one of which they call taxinchan. There are also others very large and very poisonous, with rattles in their tails. Others there are so large that they will swallow a hare, or two, but are not harmful; it is to be related that some of the Indians take hold of both kinds, without being harmed.
There is a kind of lizard, larger than ours here, of which it is surprising the great fear the Indians have of them, for they say that for them merely to touch a person causes a sweat that is a deadly poison. There are many scorpions among the rocks, but they are not as poisonous as those here in Spain.
There is a kind of large ants whose bite is very bad, and which pains and suppurates more than that of the scorpions, and lasts twice as long, as I know by experience. There are two kinds of spiders, one small and very pestiferous, and the other very large and ail covered with very fine black spines that look like down, and which hold the poison; thus the Indians are most careful not to touch them. There are many other reptiles that are not poisonous. There is a small red worm of which they make a yellow ointment that is excellent for swellings and sores, and needing no more than to crush and apply them; it also serves as oil for painting vases and strengthening the paint.