Abstract: An insect trap is provided for use in combination with an open mouthed receptacle such as a conventional canning jar. The insect trap comprises a tubular core member extending a predetermined distance into the receptacle as a passageway for insects such as houseflys, and a cap member into which the core member slides, and in which the core member is snappingly held. The core and cap members each include opposed orifices which, when aligned, permit entry of insects, particularly flying insects, into the receptacle via the passageway. The insect trap also includes a member for suspending the core and cap member assemblage in the receptacle mouth. Also preferably included are guide members associated with the cap and core members so that the orifices in the assemblage are correctly aligned without requiring visual acuity.