I have written about cicadas in In the Garden, here is Ned's drawing of a cicada from page 22.
There are signs of cicadas everywhere in the garden, you can find old skins - still attached to trees or walls.
Cicadas climb out of the ground where they have been living in a juvenile form, called nymphs. It moults, sheds its skin, and then flies off to find a mate.
Sparrows in my garden are having a cicada feast. It is quite impressive to see a small sparrow eating one of these large insects. I didn't see any sparrows eating them earlier in the summer. I wonder if they catch cicadas in late summer/autumn when a different species of cicada has emerged? I read that adult cicadas only live for 2 to 3 weeks, so perhaps the sparrows are catching the dying cicadas?
Te Ara - the Encyclopedia of New Zealand has some interesting information about cicadas, as well as recordings of cicada songs. If you want to read about the evolution of New Zealand's cicadas, as well as the regional differences, I recommend Ghosts of Gondwana: the history of life in New Zealand by George Gibbs.