Believe it or not that is one fancy fly trap my Daughter designed for me this summer.. We put some fruit juice, slice of lime and a bit of bacon in. Works like a charm, haven't seen this many dead Flys since some horror movie in the 70's.
Take one empty 2 liter plastic soda bottle, cut top 1/3 off, stick mouth end down into remainder of cut bottle, tape around with fashionable duct tape, insert ingredients and let the feast begin. They go in off the bat and won't come out.
This one has been on my back patio table since end of June and is still working nicely. Like a good bottle of wine keeps getting better with age.
Yours in the Bond