The original stimulus which started KENNETH SPENCER on a study of the Agro myzid flies was an invitation, which he accepted, to translate from the German the monograph on Leaf Miners by Professor E. M. HERING. From this developed nearly 20 years of collaboration until Professor HERING's death in 1967. Dr. SPENCER has himself described over 600 new species in the family, many of which he collected and reared from known host plants during his extensive travels to all the five main continents. Largely as a result of his work, the number of species known in Britain has increased from 90 in 1945...