This model has been printed for a regular mouth Mason Jar, and with 2 inches of Apple Cider Vinegar in the bottom of the jar, it works great!
OpenSCAD file to create Mason Jar lids with a cone shaped hole to act as a fruit fly trap. Use the Customizer settings to adjust for the following:
-Jar Size (regular or wide mouth)
-Top Opening Diameter
-Cone Height
-Bug Entry Hole Diameter (Max. 10mm, this could probably be used as a housefly/bee trap also)
The author hasn't provided the model origin yet.