All Scarab larvae are C shaped, they're called grubs and are pale yellow or white. We have lots of grubs in our compost and i pick them and feed them to our chickens. The grubs i find are Stag beetles, Rhino bugs or June beetles. Most adult beetles are nocturnal and sometimes I go on the street at night and catch lots of male stag beetles. The scarab larvae normally eat plant roots, Scarab beetles eat fruits,fungi and carrion.
The life cycle of a scarab is egg,larvae,pupa and adult. They're really hard to identify as grubs so you have to wait until they've hatched to find out what they are.
If you will like to see my other post about the rhino bug which is in the scarab family then click here http://prayingmantisworld.blogspot.com/2014/06/rhino-bug.html