unknown cocoon and pupa

unknown cocoon and pupa

Observation - unknown cocoon and pupa. Description: Found a number of these cocoons attached to the underside of young birch saplings. Most appeared to have been predated, bt found this one still containing the pupa, although it was damaged. Looks like a moth or butterfly pupa to me as can make out the a

Found a number of these cocoons attached to the underside of young birch saplings. Most appeared to have been predated, bt found this one still containing the pupa, although it was damaged. Looks like a moth or butterfly pupa to me as can make out the antenae and wings. Cocoon is pearly white with hint of yellow.