Leafcutter bees - megachile sp.

Bee watchers often first discover these amazing 6 to 15 mm long bees when they notice rows of neat circular cuts on the edges of some  leaves in their garden. 

Leafcutters use the disks of leaf as a nest building material. They particularly like the soft leaves of roses, Bauhinia and Buddleja.  

Information sourced from Aussie Bee and photo credit Erical Siegel. www.aussiebee.com.au/leafcutter_bee.html