Unidentified pupa

Unidentified pupa

Observation - Unidentified pupa. Description: Found in a small, urban garden, this appeared to be some sort of pupa. However, what eventually hatched out of it was two medium-sized flies - on closer inspection it appears whatever was in the pupa may have been parasitised? (There seemed to be fly pupa

Found in a small, urban garden, this appeared to be some sort of pupa. However, what eventually hatched out of it was two medium-sized flies - on closer inspection it appears whatever was in the pupa may have been parasitised? (There seemed to be fly pupae within it.) I'd like to know what made the original casing!