Fly Trap for hornets, house flies and fruit flies.

thingiverse

This fly trap is fully customizable for any bottle or cone size. I used a Gatorade bottle, but you can easily change the rim variable to suit your needs. You have complete control over parameters such as cone size, hole opening, small hole, rim size, and thread size. The design does not produce a single thread, instead creating two nibs that effectively catch threads. A 7mm version is included for capturing hornets or house flies, while a 2mm version targets fruit flies. The openSCAD file allows you to modify the design as desired.