Male prairie mole crickets, Gryllotalpa major Saussure, studied in Oklahoma, sing sexual advertisement songs from constructed burrows in the soil. Here we report on variation in shape of the acoustic burrow mouth not previously described for this or other mole cricket species. We have identified six distinct shapes, of which only the ‘slit’ form has been previously described. Since the surface opening acts as the system ‘radiator’, we hypothesized that variation in the shape would account for at least some of the measured variation documented since 1993 in the songs produced by the population studied. We looked for patterns in the variation of dominant frequency of advertisement calls and maximum amplitude of calls that were linked to shape of burrow openings, but found none. Future work will focus on the role of previously documented weak higher harmonics in the G. major calling song, which might vary with differences in burrow mouth shape.