Usually all you see of this insect is a flash of yellow as it flys out of your way.
Classification
from Australian Faunal Directory
Order Orthoptera - Grasshoppers, Crickets and Katydids, 1562 named species in Australia
Suborder Caelifera - Grasshoppers, 469 species in Australia
Family Acrididae - Grasshoppers and Locusts, 286 species in Australia
Genus Gastrimargus
Species Gastrimargus musicus