Identification of Male Tegenaria Spiders
The following is a technical guide to aid in the identification of house spider males. To do so, you will need a microscope of a very good hand lens. Refer to http://whatcom.wsu.edu/ag/homehort/pest/hobo.html for descriptions of other characters but the following seems most reliable. This information and images have been compiled by content on Darwin Vest's web page: http://hobospider.org/. The Burke Museum (Rod Crawford & Darwin Vest) and Dr. Antonelli (WSU Puyallup) provided the diagnostics for the pedipalps. For an excellent, easy-to-use resource to identify Hobo Spiders, visit: http://pep.wsu.edu/pdf/PLS116_1.pdf.
Specimen Prep: Kill the spider in alcohol or by freezing. Remove the male's pedipalps (see diagram A) by holding onto the spider with one pair of tweezers and pulling off the palp with other pair.
Place the pedipalp under the microscope. Make sure your orientation is consistent with the diagram or be sure to compensate if not. The diagrams show the inside orientation of the left palp.
For all the information you ever wanted to know about house spiders, see: http://hobospider.org.
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