Spider identification is difficult at a glance, and even from photographs. Many of the key features for identifying spiders (and other arthropods) to species lie in their genitalia. In spiders, these are rather inconveniently placed underneath the body, so if one is to have a chance at getting an ID from photos, one must be able to photograph the underside in some detail.

Enter the Spi-Pot. This device is simply a tube attached over a clear viewing window, with a padded plunger used to immobilize the spider with the ventral side gently pressed to the viewing window.

I made such a device simply by taping a pill bottle (with the bottom cut off) onto a microscope slide, and used a cotton ball rolled in a tube of paper as a plunger. This was sufficient to get a decent view of the spider’s epigynum, and with careful placement of a diffused light I was able to get some pictures.  I have submitted these the bugguide.net, and have already received an ID from Kyron Basu, who identified this as a spider in the family Amaurobiidae, genus Callobius. I am hoping that with the epigynum shots I have made, the ID of this spider can be nailed to species.  Buggide is awesome.

Using a microscope slide allows the Spi-Pot to hang from a glass, exposing the ventral side of the spider.

OK, the seam holding the tube to the glass could be a bit better…

The money shot (I hope).

By the way, if you are awaiting the posting of the Weekend Expedition, I have one in the works, and am probably out photographing it as you read this. The actual shooting I got in this weekend was marginal due to the hot dry weather, and I was unable to get out at a decent hour for photography. I am remedying this with a Tuesday morning expedition to the cliffs at the base of Dallas Road in Victoria, where I hope to surprise some insects before they get super active. Wish me luck!

References

Zschokke, S., & Herberstein, M. E. (2005). Laboratory methods for maintaining and studying web-building spiders. Journal of Arachnology, 33(2), 205-213.