During the past few years, we used acoustic methods to investigate sound communication and to search for the presence and distribution of singing cicadas (Homoptera: Cicadoidea) in Slovenia, Croatia, Macedonia and S.E. Asia. For detection of high pitched songs of smaller species, e.g. Cicadetta or Tettigetta the use of a bat detector - in our case Ultra Sound Advice 5-25 with the microphone mounted to a Telinga parabola - proved to be very suitable, as reported already at the IBAC conference in Potsdam. We use it mainly in the heterodyne mode with the frequency selector tuned to the lowest frequency. With such equipment it is possible to detect songs of small singing cicadas even in areas with high traffic noise and at a distance of up to about 50 m. In addition to this Telinga microphones Pro 1II and Pro V Science were used for recording in combination with the DAT recorders Sony TCD-D3, -D7, -D10 and Pioneer D-C88. The latter was used mainly in the HS mode in combination with the special version of the Pro V Science microphone, with one mic capsule sensitive also in the ultrasonic range. Such a system enabled us to make recordings in the frequency range of 20 to 44000 Hz. As a result of such investigations in Slovenia, Croatia and Macedonia in the last few years many new data about songs and distribution of single species were obtained. In addition to this, during this survey we found in Slovenia not only Cicadetta montana (Scopoli) as described by Boulard (1995) but, with the aid of the bat detector, another similar and closely related species with a different song, which still has to be identified. In Macedonia this year we were able to find, record and catch on Galicica mountain yet another unidentified species with a very characteristic song, which is also closely related to Cicadetta montana. Furthermore, it was found that the species Cicadatra hyalinata (Bru1le), considered by some authors to be only a variety of C. atra (Olivier), has a different calling song and is therefore most probably a good species. Most interesting is the discovery of Cicadatra persica (Kolenati) in the Radika Gorge, not previously known from the Balcans and detected for the first time a year before during acoustic scanning of this region. The songs of this species were previously not recorded and analyzed. A detailed description of these interesting cicadas and their songs is in preparation.