Entomology (Study of Bugs)/Spider identification


spider 1
spider 1  

I live in S. California (Los Angeles for easy reference).  Attached are two photos of spiders we get at my work (wastewater treatment plant), seasonally.  They show up around the end of Spring/beginning of summer, right about the time the swallows return.  They disappear around the beginning of Fall  The place is infested with them!!  

I was hoping you might be able to identify them, and more importantly, advise if I need to be leery of them?  

I realize most spiders would rather go unnoticed and undisturbed, and just left alone, but do to the amount of them, it's inevitable I will have one crawling up a pant leg sooner or later.

If bit, does one require medical attention?

I thank you in advance for any light you can shed on them.


Nice images of the Western Spotted Orbweaver, Neoscona oaxacensis .  No, they are not the least bit dangerous.  Here is more information in a blog post I wrote about them:


Note that the species is quite variable in color and pattern.


Entomology (Study of Bugs)

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Eric R. Eaton


I answer insect and spider identification questions ONLY. Attach images if possible. No "what bit me?", "what do I feed this bug in captivity?", or science fair project questions please. NO TECHNICAL QUESTIONS ABOUT INSECT PHYSIOLOGY.


Principal author, Kaufman Field Guide to Insects of North America. Professional entomologist employed previously at University of Massachusetts, Chase Studio, Inc., and Cincinnati Zoo; contract work for West Virginia Department of Natural Resources, Smithsonian Institution, and Portland (Oregon) State University.

Author, Kaufman Field Guide to Insects of North America, Missouri Conservationist magazine, Ranger Rick, Birds & Blooms, Timeline (journal of the Ohio Historical Society). I have contributed to several books as well.

Oregon State University, undergraduate major in entomology, did not receive degree.

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One of the top 50 experts in all categories for AllExperts.com, 2009.

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Principal author of the Kaufman Field Guide to Insects of North America, Smithsonian Institution (contract), Cincinnati Zoo (employer), Portland State University (contract), Chase Studio, Inc (employer), Arkansas Museum of Discovery (guest speaker). Currently seeking speaking engagements, leadership roles at nature festivals, workshops, and ecotours.

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