These nine theoretical centres or " pieces " L'Herminier deemed to be disposed in three transverse series (rangees), namely the anterior or " prosternal," the middle or " mesosternal " and the posterior or " metasternal " - each series consisting of three portions, one median piece and two side-pieces.
- Prosoma longer than wide, its sternal area very narrow, furnished with a large prosternal and metasternal plate, and often with a small mesosternal sclerite.
Sternal area broad, with prosternal, two mesosternal, and metasternal plates, the prosternum projecting forwards beneath the coxae of the 2nd pair of appendages.
The sternal surface wide, continuously chitinized, but with prosternal and metasternal FIG.
Its ventral surface provided with one prosternal, two mesosternal and one metasternal plate.