From my search there appears to be no such species as Agrotis porphyrinaria. I agree with Don, do you mean Agrotis porphyricollis ? I have undone the confirmation of Agrotis porphyrinaria and suggested A. porphyricollis. I have also deleted Agrotis porphyrinaria from the taxonomy.
Agreed, I can't find any reference to A. porphyrinarea or even porphyrinara/porphyrinuria alone. The specimen seems to fall within the large degree of variation apparently possible within A. porphyricollis.