The fate of γ‐benzene hexachloride in resistant and susceptible houseflies. III.

A detailed study of the minor constituents of the carbon tetrachloride extracts of γ‐BHC‐treated flies has established the presence of pentachlorocyclohexene, trichloro‐benzene and acidic substances. Under various conditions of exposure and different dosage rates these compounds occur only in small amount (3% or less of the absorbed dose of γ‐BHC). Pentachlorocyclohexene was never found in quantities greater than 3% of the γ‐BHC absorbed and it is concluded that if this compound is an intermediate in the metabolism of γ‐BHC by resistant houseflies, it has, in the γ‐BHC‐resistant Uruguay strain, only a very transient existence. One result of the discovery of these minor constituents in carbon tetrachloride extracts is to show that the resistant strain enjoys a greater advantage over the susceptible in rate of detoxication of γ‐BHC than had previously been supposed.