Mouthparts of six species of chironomid larvae were compared on both an intra- and inter-specific level. The species were: Chironomus riparius, Cryptochironomus defectus gr., Endochironomus albipennis, Glyptotendipes pallens, Microtendipes pedellus and Parachironomus arcuatus. The mouthpart morphology in C. defectus gr. and P. arcuatus is considerably different from the four other species and changes little between instars. Within C. riparius, E. albipennis, G. pallens and M. pedellus there is a considerable difference in the mouthpart morphology between the first instar and the remaining instars. The morphology of the mouthparts of the first instar of C. riparius, E. albipennis, G. pallens and M. pedellus resembles in many ways that found in C. defectus gr. and P. arcuatus.