Contents

04 June 1965
Vol 148, Issue 3675

About The Cover

Melanism in insects inhabiting industrial environments is one of the most striking evolutionary changes occurring today. Extensive investigations of Biston (Amphidasys) betularia (peppered moth) reveal that its black form, carbonaria, may constitute up to 98 percent of industrial populations. The black form has a 30-percent chance of survival over f. typicaon blackened tree trunks. A mechanism may exits in the gene complex, and may insure dominance of the black form at each mutation. See page 1290. [H. B. D. Kettlewell, University of Oxford]