Entomologica Romanica Vol. 21 / 2017
2017
Fig. 1. Frequency of the Biston betularia forms from the intensly polluted sites in the year 1987 and 2012 Fig. 2. Frequency of the Biston betularia forms from the medium polluted sites in the year 1987 and 2012 Fig. 3. Frequency of the Biston betularia forms from the unpolluted sites in the year 1987 and 2012 7