This pretty viper was one of our top targets for this trip. Fred Muller found this pretty fella after we spent an hour or so climbing up and down a steep hill looking for the trail. We never did find the trail.

Here is a list of all the reptiles and frogs I saw on this trip to Guatemala.

Fred found this somewhat larger individual the next night. Wikipedia claims that "bicolor" refers to the contrasting ventral and dorsal colors. This could be true, but since that contrast is a common feature in snakes it seems more likely that "bicolor" refers to the blue/turquoise skin between the green scales.