switch means coupled to {HEAD ~ a source} of electrical energy and to said pump for selectively energizing said {TAIL ~ pump}, said switch means including: 
switch means coupled to { HEAD ~ a source } of electrical energy and to said pump for selectively energizing said { TAIL ~ pump } , said switch means including :
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH