Creosote Litter Leaf Beetle
Pachybrachis mellitus
In reality this beetle does not have an official common name. Finding one of these minute beetles requires a lot of uncommon searching ... many days and bushes might be searched without finding a one. This pair was found on fresh growth of Creosote Bush (Larrea tridentata) near Bulldog Canyon in the Goldfield Mountains, Maricopa Co., Arizona on 11 Oct. 2008.
Chrysomelidae -- Leaf Beetle Family
Like all holometabolous insects, this leaf beetle leads a double life. When it first hatches from the egg it is a worm-like grub. It lives within a case constructed from fecal material and lives on the ground within the leaf litter. There it feeds on dead leafs and such - presumably dead creosote bush leaves. Eventually the mature grub forms a pupa which later ecloses into the adult beetle pictured at left. The adult beetles are less than 4 mm long and are well camouflaged - they are present in spring and autumn when there is fresh growth.