{HEAD ~ The insecticides} contain Propoxur, Pyretrines, silicates and {TAIL ~ a combustible wax} 
contain
{ HEAD ~ The insecticides } contain Propoxur , Pyretrines , silicates and { TAIL ~ a combustible wax }
HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL