Window Screen Repair

[Rosy-WO]

I have a Que and the screens on the windows roll up and down, which works great, but one of my helpful (?) grandchildren managed to poke his finger through the screen when sliding it in place which caused the screen to come out of the channel. there doesn't appear to be the regular spline to fit back into the slot so I am not sure how to repair this. Help please!

Rosy Que