I can still remember my delight as a child when I found a catasarcus weevil, put it on a finger, and felt it hanging on for dear life as I tried to remove it. Weevils are harmless, galumph along and look cute. This link provides an excellent introduction.
a very general rule of thumb is the longer the snout the deeper the eggs are laid.
The Haplonyx species (pear-shaped weevil) was about to drill into a Drummonds mallee bud.
The file below describes the life cycle of another Haplonyx species
Large weevils are similar. Catasarcus weevil larvae chew eucalypt roots, and Leptopius species (wattle pigs) chew acacia roots. Both pupate underground. This Foxypress recounts fossilised Leptopius pupal cases (clogs) that I found at Mukinbudin.