I sprayed for earwigs on my back patio and I found this guy. It's hard to tell in the pic but his legs/upper body are bright red and his bulbous bottom is green. I've been told it's probably poisonous and I have a 2 year old daughter that plays out there...please help if you can. I am in Illinois if that helps anyone. Thanks!
Although the image is not clear enough for me to give you a specific identification, I can assure you that it is not a dangerous species. It could belong to at least two different families; Dysderidae (woodlouse spiders) - see http://tinyurl.com/23e6zwn for an example, or Corinnidae (ground sac spiders) - see http://tinyurl.com/2384ph7 for an example. With the exception of one very small family (Uloboridae), all spiders are venomous; it is just a very few species having the combination of potent venom and jaws strong enough to penetrate human skin that truly are dangerous. See the 'sticky' at the top of this forum for more information.
Here is a photo of it after it died...maybe this is a little clearer...
This definitely is a woodlouse spider (Dysdera crocata); they have large jaws for their size, and can give you a painful bite if you pick one up carelessly, but they are not dangerous to humans.
