Ventral tubular ducts
The structure of the tubular ducts on the venter is similar to that of those on the dorsum and, like them, their structure and distribution are important taxonomic characters. When present, most species have only one type of dorsal and one type of ventral tubular duct
With small outer duct, sclerotised cup shaped invagination and invisible inner duct
With medium sized outer duct, sclerotised cup shaped invagination and small inner duct
With long outer duct having sclerotised anterior end, sclerotized cup shaped invagination and narrow medium sized inner duct with flower shaped terminal gland
With long outer duct, sclerotized cup shaped invagination and broad (as broad as outer duct) medium sized inner duct with flower shaped terminal gland
With long outer duct, sclerotized cup shaped invagination and medium sized inner duct having narrow proxinmal end and broader distal end and flower shaped terminal gland
With short outer duct, sclerotized cup shaped invagination and long inner duct (longer than outer duct) with flower shaped terminal gland
With short outer duct, sclerotized cup shaped invagination and very long inner duct with flower shaped terminal gland
With midum outer duct, sclerotized cup shaped invagination and inflated inner duct having narrow proximal end and wide distal end and flower shaped terminal gland
