"Fieldnotes," January 5th & 6th, 2014: "Jumping Spiders," by Sallie Sills. http://www.montananaturalist.org/
"The spider made its way over the smallish, multicolored rocks. So did I. A fly landed on a low rock a number of inches from the spider. The spider's abdomen tilted back, away from its cephalothorax, and then it pounced. It literally jumped right onto the spot where the fly was resting. It was quick, but the fly was even quicker. Although I was trying to be stealthy, I stumbled loudly. The spider whipped itself around and stared at me - it stared so long that I became somewhat unnerved."