Yellow Monday Cicada or Greengrocer ( Cyclochila australasiae ) The Green Grocer Cicada is a common cicada along eastern Australia. It has a loud high pitched call and is one of the loudest insects in the world. The most common form is green, and another fairly common form is the yellow form (the Yellow Monday). Less common colour variations are dark tan (Chocolate Soldier) and turquoise blue (Blue Moon). Most forms have red eyes, although the Blue Form has purple blue eyes. The Masked Devil is an orange brown form with a black mask across the eyes that is more common at higher altitudes.