Stereo pairs of epigynum (female genitalic structure). The larger pair is designed for cross-eyed viewing, the smaller pair for parallel viewing. (Both pairs are one big image, to stay under the posting limit.)
There's a story here, of course.
A couple of months ago, I posted an action picture of a small spider that might (or might not) be a hobo.
Eight weeks, three molts, and more than a few flies later, I sent an email to Rod Crawford, curator of arachnids at the University of Washington's Burke Museum.
The reply (by permission, and in its entirety as requested) was this:I'm writing to you now to ask if you can help me ID a spider. A couple of photos are attached -- I don't know if they'll be adequate, but thought I'd ask now before going to the trouble to shoot better ones.
Background story is that this individual was captured live a couple of months ago by one of our summer interns at Pacific Northwest National Lab in Richland, WA.
She thought from general appearance that it might be a hobo, and asked if I could tell for sure. Well, it was only about half-grown, so I couldn't, but I did keep the beast around to see if perhaps I could get it to grow up.
Appearance when young is shown at http://www.photomacrography.net/forum/v ... php?t=3081 .
Three molts later, it now looks to me like a mature female whose epigynum structure matches the hobo in Figure 10 at http://pep.wsu.edu/pdf/PLS116_1.pdf . The coloration of mine is much less intense, but I gather that's not a strong point.
Anyway, I wonder if you can confirm, deny, or correct the ID, or let me know how much better or different pictures you would need to do that.
Many thanks to Rod for the ID and further information -- and of course I'm always eager to help dispel myths about our segmented brethren!Rod Crawford wrote:Yes, I think your diagnosis is correct. It's no surprise - hobo spiders are common in every town and farming area of eastern Washington, but human bites are still rare. Females, like yours, are only minimally toxic to vertebrates - all the serious bites are from males (all dead by this time of year) and possibly juveniles.
Congratulations on hitting on the one thing to photograph that would make an ID possible. Very few people ever get past the wrong idea that coloration means something in spider ID.
---Rod Crawford, Burke Museum, Seattle, USA <firstname.lastname@example.org>
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Check out the "Spider Myths Web Site"!
http://www.washington.edu/burkemuseum/s ... index.html
and find out why everything "everybody knows" about spiders is wrong!
Technical: Canon 300D. First two images using Sigma 105mm macro lens at 1:1, flash with paper towel diffuser. The subject was on its web, inside a square, clear, plastic box, photos shot through the sides of the box.
Details of the epigynum are stacked with Helicon Focus, shot with Olympus 38mm bellows macro lens set at f/5.6, 0.005" focus step. Dual fiber halogen illuminator with kleenex tissue diffuser. Live subject was confined in a "dry box" between two microscope slides, as described by this posting in the technical forum.