a source of octenol, separate from {HEAD ~ the canister} containing {TAIL ~ carbon dioxide}, provided in the housing 
containing
a source of octenol , separate from { HEAD ~ the canister } containing { TAIL ~ carbon dioxide } , provided in the housing
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH