The fourth pair of sternal setaesternal setae:
in Mesostigmata, the five pairs of setae in the intercoxal region designated st1-5; st1-3 are present in the larva and usually are borne on a sternal shield in the adult female; st4, the metasternal setae, are added in the deutonymph, often are borne on metasternal platelets, and sometimes on the sternal shield; st5, the genital setae, are added in the protonymph and usually borne on or are inserted laterad the epigynal shield in the adult female.
are called "metasternal setae (st4)"
They are free from the sternal shieldsternal shield:
a shield in the anterior intercoxal region of parasitiform mites that bears one or more pairs of sternal setae.
in most Gamasina, either in the soft cuticle or on metasternal platelets with stp3. The metasternal setae are sometimes captured by the endopodal shield at the basebase:
the usually columnar basal part of the tritosternum; sometimes expanded and rectangular or otherwise modified; the most basal part of any structure.
of coxae IV.
Exceptions occur in most Rhodacaroidea and some Eviphidoidea and Veigaia (see Setae on strnal shield(s) feature page)
Author: David E. Walter
Content last updated Sept. 2006, unless indicated otherwise
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