Application for a non-US Resident

My boss holds a US Visa (non-US resident) and needs a China Visa. I was informed that he will need to go "in person" to the Chicago Consulate. I was also told that he must supply an additional form, stamped by the local Chinese government, this is in addition to his Invitation Letter. Do you know where I can find this additional form - I was not given the name of it?