Arthur is a caterpillar-in-waiting. He is waiting to become a moth
and has built himself a chrysalis in readiness for the day. However this
awaited transformation to mothness has been a long time in coming and during
this waiting period Arthur has built up a wealth of useless information
that he is all too ready to impart to anyone who will listen. He is like
a London cab driver - an opinion on every topic. Sadly, for Arthur, he
is nowhere near as clever as he thinks he is. Consequently, he is more
than happy to 'hang out' with Mavis because she makes him feel superior.
He is quite nervous of Evil Edna and avoids crossing her.