WAmmodesmidae
WAndrognathidae
WAnthroleucosomatidae
WArthrosphaeridae
WBlaniulidae
WCambalidae
WChelodesmidae
WCraspedosoma
WDalodesmidae
WEuphoberiidae
WEuryuridae
WGlomeridae
WGomphodesmidae
WHaplodesmidae
WHarpagophoridae
WHirudisomatidae
WIulomorphidae
WJulidae
WLophoproctidae
WMetopidiotrichidae
WNearctodesmidae
WPachybolidae
WPaeromopodidae
WPalaeosoma
WParacortinidae
WParadoxosomatidae
WParajulidae
WPlatyrhacidae
WPleurojulidae
WPolydesmidae
WPolyxenidae
WProcyliosoma
WPyrgodesmidae
WRhinocricidae
WSchizopetalidae
WSinocallipus
WSiphoniulus
WSiphonocryptida
WSiphonorhinidae
WSphaerotheriidae
WSpirobolellidae
WSpirobolidae
WSpirostreptidae
WStemmiulidae
WSynxenidae
WUrochordeuma
WXyloiulus
WXystodesmidae
WZephroniidae
WZosterogrammidae