During a physiological investigation of myrmeleontid larvae it became apparent that my material included three different species. These are: Euroleon nostras (Fourc.) Myrmeleon bore (Tjed.) and M. formicarius L. I have studied the larval characteristics of these and have reared them to imagines. Two determination keys are given, one for living larvae of all instars, the other for dried or alcohol-preserved larvae of the second and third instars.