The Crested Tooth-grinder, Ecphantus quadrilobus Stål, Acrididae; Catantopinae
The Crested Tooth-grinder is a common grasshopper in disturbed and open rangelands, and pastures in Australia. It prefers habitats with grey herbaceous vegetation. E. quadrilobus occurs broadly across the continent from coast to coast. It is a very distinctive grasshopper and cannot be confused with any other. It is quite hairy, as are many other grasshoppers that are associated with greyish herbaceous vegetation, and it has a distinctive crest. Green and greyish morphs can be found at the same place with the greenish grasshoppers being the more common.
Fifth instar nymph of E. quadrilobus. The four projections of the pronotum account for its name.
One weird feature of this grasshopper is that when it is hand-held it grinds its mandibles together to create a squeaking sound. This is not unique in grasshoppers but it is startling when you first encounter it. And that is probably the whole point. Were you a lizard or bird, you might drop the prey as the sound might be quite similar to that of a bee or wasp under duress.