The spar includes {HEAD ~ a female receptacle} that receives {TAIL ~ a male blade} from the closeout skin assembly 
The spar includes { HEAD ~ a female receptacle } that receives { TAIL ~ a male blade } from the closeout skin assembly
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH