It’s been four months since my last Webnesday post. I thought I’d have to wait a lot longer than this for my next arachnid offering, but just the other night, as I was crawling into bed and reached for my glass of water, I saw that one of our most common ones, a black-footed or yellow sac spider (Cheiracanthium mildiae), had been waiting in the wings—well, okay, in a fold of the curtains—for a screen test. Of course, I was only happy to give it the chance to see how it would look through the camera, so I quietly re-donned a modicum of garb, tiptoed out of the room, sprinted to get the camera and the tripod, and tiptoed back. It was still there and and was content to wait patiently while I set up for a few different angles and degrees of proximity.
The name “yellow sac” comes from their protective web. They don’t build a web to catch prey, but are active hunters; they spin a small web quite similar to a one-person bivouac tent that a mountain climber might use and rest within its protection, usually in a corner where a wall meets a ceiling. This diffuses their form and makes them more difficult to see. Oh, and by the way, remember that this wee beastie is quite small, with a total leg span of less than an inch (about 2 cm). If you’d like even more detail, just click on one of the photos and you will be rewarded.