Intercoxal Region of Adult Female

The sternal region of the podosoma is formed differently in acariform and parasitiform mites.  In the Parasitiformes, the leg coxae articulate with the body and the intercoxal region is occupied by sternal elements anteriorly and anteriorly intruding genital elements posteriorly.  The sternal elements are well sclerotized in the Holothyrida and Mesostigmata, typically in the form of a large sternal shield (sometimes fragmented). 

Primitively in Acariformes, the leg coxae are fused to the body wall to form individual epimera, which tend to fuse together into 1-2 regions in more derived lineages, or when sclerotization is reduced, to become reduced to coxal plates or internal apodemes.