Naturalis (Leiden Museum, Holland) has digitalised a large part of their butterfly collection.
It is very rich in historic specimens from former Dutch colonies (Indonesia, Papua...) and some other specimens. Very useful to see some rare species AND their collecting data.
An example with Delias clathrata, they have access to 15 specimens : https://bioportal.naturalis.nl/nl/resul ... perator=OR
A nice specimen caught by my friend Fred Gerrits
As discussed with Chuck in another topic, this is the kind of digitalization all big private collections should do too (yes, it takes time & money).
Check their database on your favourites genera.