Currently viewing the category: "Ground Spiders and Ant Mimics"
What's That Bug? does not endorse extermination

Subject:  Spider
Geographic location of the bug:  Los Angeles, California, USA
Date: 05/04/2019
Time: 02:21 AM EDT
Your letter to the bugman:  I found this spider on the wall of our house- outside. It’s May 4th (May the 4th be with you.)
How you want your letter signed:  Allison

Ant Mimic Spider

Dear Allison,
This is a harmless Ant Mimic Spider in the genus
Castianeira, and it is most likely Castianeira occidens, which is native to Southern California and which is pictured on both BugGuide and the Natural History of Orange County.  We do have our doubts as its markings more closely resemble Castianeira crocata , which is pictured on BugGuide, and also the Red Spotted Ant Mimic Spider, Castianeira descripta, which is also pictured on BugGuide, but both of those are eastern species.  It is not entirely impossible that one of the eastern species might have been introduced to Southern California.  The species identification confusion is also noted on BugGuide where it states:  “The following ID tips come from Reiskind, 1969. Corresponding page numbers are listed below. …  The next group is C. crocata (pg. 200), C. descripta (pg.208), C. occidens (pg.211) & C. floridana (pg.201). C. occidens can be separated from the other two by the white stripe on the carapace. At this point we aren’t sure we can separate C. crocata & C. descripta. It’s possible that the red mark goes all the way to the rear in C. descripta and stops short in C. crocata. Also, males of C. descripta have ‘some white hairs at the posterior end’. C. floridana is easier to separate because it’s only found in peninsular Florida, but range may overlap with C. descripta.”

What's That Bug? does not endorse extermination

Subject: Pretty spider
Location: Stillwater OK
July 22, 2017 6:07 am
Found this spider in my dining room this morning. I’ve never seen one like this before.
Signature: Angela

Ant Mimic Ground Sac Spider

Dear Angela,
This is one of the Ant Mimic Ground Sac Spiders in the family Corinnidae, and we are confident we have identified is as a species with no common name,
Castianeira amoena, thanks to images on BugGuide.  According to SpiderBytes:  “Some Castianeira species are thought to mimic velvet ants (Mutillidae), rather than ants. Mutillids are not actually ants but wasps, and the females are wingless and brightly coloured, with extremely painful stings. In this case, harmless Castianeira spiders might benefit by looking like the much more dangerous velvet ants, and thus be avoided by predators (this is called Batesian mimicry).”

What's That Bug? does not endorse extermination

Subject: Castianeira crocata?
Location: Southwest Missouri
May 18, 2017 12:27 pm
Is this a Castianeira crocata? I’ve never seen this one before. Just found it in my basement.
Signature: TK

Ground Spider

Dear TK,
You are correct.  This is a Ground Spider,
Castianeira crocata, and BugGuide does not list a common name.  According to SpiderzRule, a close relative in the same genus, Castianeira descripta, is commonly called a Red Spotted Ant Mimic Spider.  This is not considered a dangerous species to humans.

What's That Bug? does not endorse extermination

Subject: love bug
Location: Kelowna, British Columbia, Canada
May 18, 2016 11:44 am
Hello 😀
This punk jumped on my face in the night, a couple weeks back.. I tried to catch him, but he escaped.
Today however, I caught him going about his business speedily, high up on the wall.
Having a hard time identifying this lovely specimen… Please help.
Much love to all the insect lovers ♡
Signature: Tina Marie

Ground Spider

Ground Spider

Subject: sneaky punks
Location: Keliwna, British Columbia, Canada
May 21, 2016 4:50 pm
Hello Bugman.. I sent a similar identification request just the other day. Same spider type, different specimen.. This one being larger and more photogenic. Excited for an ID on these guys. Love your website!!!
Signature: Tina Marie

Ground Spider

Ground Spider

Dear Tina Marie,
We went back through our unanswered mail to locate your original submission.  We believe both of your spiders are the same species of Ground Spider in the family Gnaphosidae, and that species is
Sergiolus montanus based on this BugGuide image.  According to BugGuide:  “There appears to be quite a bit of variation in the abdominal patterning of this species. A microscopic exam of the spider’s genitalia is typically necessary for accurate identification.”

Ground Spider

Ground Spider

What's That Bug? does not endorse extermination

Subject: Strange looking spider named clint eastwood?
Location: New Jersey, USA
March 20, 2016 12:09 pm
What is this thing?
Signature: F

Ground Spider

Ground Spider

Dear F.,
This is a harmless Ground Spider,
Sergiolus capulatus.

What's That Bug? does not endorse extermination

Subject: Spider
Location: St louis Missuri
March 9, 2016 11:06 pm
What type of spider is this ?
Is it poisinus?
Signature: Spider man

Parson Spider

Parson Spider

Dear Spider man,
This distinctive spider is a Parson Spider in the genus 
Herpyllus, probably Herpyllus ecclesiasticus.  Like most spiders, it has venom, and like most spiders, it is not considered dangerous to humans.  It is unlikely that it will bite a person, and if a bite does occur, there will likely be nothing more than local irritation.

What's That Bug? does not endorse extermination