Special techniques are necessary to study the morphology of complex chitinous structures such as insect mouthparts. Many of the details are beyond the resolution of light microscopy, and the methods of conventional electron microscopy do not include the efficient production of serial sections for reconstruction. Although the scanning electron microscope (SEM) permits detailed observation of 3-dimensional surfaces, it cannot see internal surfaces and under complex folds, nor can it readily show the thickness of solid structures. To study the details of the stylet tips of the bug Rhodnius prolixus (Stål) several techniques were tried. Initially, specimens had been embedded in paraffin wax, sectioned, dewaxed, and prepared for the scanning electron microscope. Because of difficulties in sectioning the hard stylets and poor preservation of fine structure, this method was abandoned in favour of one using thick sections (2 μm) of material embedded in a mixture of Epon and Araldite.