Improvements in the techniques for observation and preparation of polytene chromosomes from Anopheline mosquitoes are reported. The improvements are as follows: an observation method for polytene chromosomes using both phase-contrast and interference microscopy with the same microscope; an improved polytene chromosome preparation technique, a field collection method and a rearing method for obtaining excellent material for cytogenetic research and investigation. The described methods were successful for certain species complexes for which poor results were obtained using previously described methods. These techniques are useful not only for laboratory research but also for field investigations and the cytotaxonomical identifications of malaria vectors.