Acariformes

 

The Acariformes is the most diverse order of mites and includes most of the species of economic importance, e.g. spider mites, dust mites, and chiggers, as well as important soil taxa such as the Oribatida.  Acariform mites have a sternum formed from the fusion of the leg coxae to the body wall; a tritosternum is never present, but rutella may be present (most Oribatida and Endeostigmata, many Astigmata) or absent (Prostigmata, Sphaerolichida, some Endeostigmata and Astigmata).