ABSTRACT.Adults of five species of Triatominae were found to stridulate when handled:Triatoma protracta, T. lenti, T. infestans, Panstrongylus megistusandDipetalogaster maximus.All five larval stages ofD. maximuswere also found to stridulate. Stridulation is caused by the tip of the reflexed proboscis rubbing along the transversely ridged prosternal groove. Each syllable of the resulting song is produced by a single antero‐posterior movement of the proboscis and contains 80–150 intrasyllabic spikes, each corresponding to the striking of a single ridge in the prosternal groove. Analysis of tape recordings of the songs showed that all species have a broad frequency band without well‐defined maxima, extending into the ultrasonic with frequencies of up to 50–100 kHz. The lowest frequency produced by each species is consistent with the repetition rate of the striking of prosternal ridges by the proboscis. No behavioural response to the replayed song was detected, but when the song was replayed to femaleP. megistusthe frequency of action potentials within the antennal nerve correlated well with the intrasyllabic spike frequency of the replayed song. Possible microphonic artefacts were not, however, excluded. Possible functions of the song are di