Peregrinus maidis (AsmeadXHemiptera. Delphacidae) is the only known vector of Maize mosaic virus and Matze stripe virus, two circulative and propagative viruses. The feeding behaviour of P. maidis was investigated with electrical penetration graph technique (DC-EPG). Five different waveforms were characterised. Based on the correlation between waveforms and the fine structure of stylet pathways observed by transmission electron microscopy, active ingestion was restricted to xylem vessels, whereas passive ingestion and watery salivation occurred intermittently in sieve tubes. Spectral and time frequencies analysis of digital data obtained with the "'EPG-Soft" software improved the distinction between ingestion and salivation activities in sieve tubes. Ingestion and watery salivation are essential phases of the feeding behaviour of piercing sucking insects, in relation to acquisition and inoculation of circulative viruses.