Please help me with identification of what I assume to be a larval stage of an insect, in a S.E.London garden. There are a number of these in the garden concerned, ranging from 3 to 6mm in length. They are quite mobile, so I assume they have legs, even though I didn't actually see any. Thanks.
You are correct, this is the larval stage of what is commonly known as Mealybug Destroyer or Mealybug Ladybird (Cryptolaemus montrouzieri). They are in the Ladybird family of beetles. They are native to New Zealand and Australia however they are commonly used as a pest control for green houses. Its been reported that they are not native to the UK and can not survive our winters, but I've had the larva in my back garden for years, have yet to see an adult but every year we see the larva. Saw my first of the year just yesterday. They are good for the garden so don't worry