Legal Question in Landlord & Tenant Law in Illinois

Insufficient information. Do you have a lease? How do you know these are bed bugs? Are you in student housing (your zip is DeKalb - NIU)? Was this a furnished place or did you supply the furniture/bedding? When you moved in was there any kind of written inspection list identifying the issue? Have you spoken to the landlord? The Illinois Department of Public Health, the county and local health and building departments, all may be resources too. You're in better shape if the place was rented as furnished with bedding, although bugs can travel in linens if they are yours. Your landlord should provide a copy of the exterminating bill - for all you know it's for the entire building and the landlord is just trying to apportion it out when the landlord should be absorbing it in the lease. DeKalb also appears to have a landlord-tenant ordinance and tenant bill of rights (local ordinance) that may be applicable (go to the site and look at right #9 in particular -- to have a "habitable" place):

http://www.niu.edu/Legal/topics/landlord/dekalb.shtml