Large, black, furry jumping spider
I found this unusually large jumping spider on one of the roof support pillars on our front porch on July 18, 2011. He was a big, black, furry, sinister-looking specimen, over a centimeter long.
Normally, jumping spiders are kind of cute, but this one has more the air of the insect murderer that he actually is.
In this closeup of his face, we see that he’s got iridescent green chelicerae (his mouthparts), so he’s probably one of the Phidippus jumping spiders.
Jumping spiders use all four of their rearmost legs for jumping. In this next picture, you can see the very hind pair shaped something like a grasshopper’s hind legs, all ready to push backwards. The pair in front of that are oriented a little bit differently, so that when he jumps they will pull forward rather than pushing backwards.
To show how this works, here’s a short video I found on YouTube that was shot with a high-speed camera.
I think the use of four legs for jumping rather than just two gives him far more control than most small jumping arthropods have. And he needs precision very much. Things like grasshoppers, leafhoppers, and fleas are using their jumping abilities to escape from predators, so they don’t care about fine directional control. They just want to get away. Jumping spiders, on the other hand, are using their jumps to intercept. They don’t have to jump far, but they do have to have pinpoint precision.
 In the picture, it looks like he has human-like eyes. That’s an artifact of the way my Cone Macro Flash Concentrator directs light from the camera flash. The white “iris” is a reflection of the posterboard cone that most of the light from the flash is bouncing off of; the black “pupil” is the circular end of my camera lens; and the glowing-white spot in the middle that makes him look demonical is the light that traveled directly from the on-camera flash and bounced back from his eye. And what looks like a baggy lower eyelid is a reflection of a corner of the white sheet of paper he’s standing on. It’s just a coincidence that it all lined up to look like human eyeballs, I swear!
 There is a note on YouTube from the person who posted this video that the slow light-dark strobing of the background brightness was due to being shot under fluorescent lights, which flicker either 100 or 120 times per second, depending on whether they are powered by 50 or 60 cycle AC. So since the brightness strobes about five times in the course of the jump, that means the jump only took about 1/20th of a second – too fast to see with the naked eye.