A small black female Tachinid fly laying an egg on a beetle larva. The fly was identified as Dufouria chalybeata (Diptera: Tachinidae) by Erikas 'neprisikiski' and Chris Raper here.
The larva is probably that of the thistle tortoise beetle, Cassida rubiginosa (Coleoptera: Chrysomelidae). It is using a fecal pellet as a shield.
Photos taken in the field below Chazey Wood, near Caversham, UK, on 2011-05-25.
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