Abdomen - Round and can be yellow, tan or slightly green.
Cephalothorax - Tiny. Usually a tan color.
Female Size - NA
Male Size - NA
Bite Info - Believe it or not, these little guys are one of the more dangerous you will find in Michigan. They are the most common spider to be bitten by and their bites are sometimes mistaken for that of the Brown Recluse. Although their venom is not nearly so dangerous as the Recluse, the bite can sometimes leave heavy swelling and even leave open sores.
THere is a lot of bad info on the net that states that the Yellow Sac Spider uses the same cytotoxin as the Recluse does, but not as potent. I have recently learned from Rick Vetter, the top Brown Recluse expert in the world, that this is not true. This bad information was started by someone who was looking to gain from causing fear. I am one of those who fell for this bad information and helped spread it. I apologize for that.
Other Notes - During the daytime these spiders often hide in a small blanket of web under leaves and wood, but often will make their way into homes and hide in corners or under window sills.
Genus - Cheiracanthium Mildei