This invention concerns the in-situ monitoring of insects, and in particular an insect inspection cylinder and trap to facilitate this monitoring. The trap comprises means to intercept flying insects and direct them to an inspection cylinder that is connected to an outlet from the means to intercept flying insects. An insect detector is associated with the cylinder to detect insects inside it, and a camera is associated with the cylinder and the detector to capture images of insects inside the cylinder. Wherein the sectional dimensions of the inspection cylinder are sized to prevent insects selected for observation from flying through it, but instead requiring them to walk through it.