131(AP)申請怎麽還要我補交140已申請的證明？

來信如下：

Please submit proof that you have submitted an underlying petition such as an I140, I-360,or I526. If you are the derivative, please provide proof of the underlying petition (I140, I-360,or I526) for the principle applicant.

我是已經拿到485收據後單獨申請的131，老公是485的主申請人。以前沒聽說申請131要交140的證明呀，應該隻要485收據就可以呀。有誰知道詳細情況？我是不是應該補交上老公的140批準通知複印件就可以了？補交的時候是不是直接寄給來信上的簽名的人？

信最下麵寫有 EMU /# XM 209 是什麽意思呀？