It would be nice to think that is exactly what the photo shows!
Dave

Jeremy Thomas says in The Butterflies of Britain and Ireland

lives concealed in an earthen cell moulded by ants beneath the vetches

which is exactly where I found this.
Dave

Chalkhill Blue pupa case 0005373.jpg I posted this on the General forum but had no reply so I thought I would try the species forum for Chalkhill blues. I went looking for Chalkhill blue larvae last week - found some but also found some ants tending a small, brown, open case which just looked perfe...

I went looking for Chalkhill blue larvae yesterday - found some but also found some ants tending a small, brown, open case which just looked perfect for a larva to pupate in. There was a lot of ant activity. I don't think it was last year's case so do the ants build the cases to put the larva/pupa i...