My association with Prof. Hering extends over the past seventeen years, and during this period I have visited him at his home on more than forty occasions and received over 300 letters from him. These letters contain much detailed entomological information. They also throw considerable light on Prof. Hering's personality and character and the background against which he worked. The publication of at least part of these letters as a final tribute to Prof. Hering has been in my mind for many years. This original idea has now been somewhat extended by the inclusion of a number ofletters to Dr. H. Buhr, Dr. J. Klimesch, Dr. F. Groschke and G. C. D. Griffiths, all of whom shared Prof. Hering's interest in leaf-miners. Although Dr. Buhr is primarily a botanist, with Hering's encour agement he has taken an active interest in leaf-miners throughout his career and his remarkable collecting becomes apparent from Hering's letters to him. For many years Prof. Hering has written between two and three thousand letters annually. It has obviously been possible to consider here only a very small proportion of these. From many of the longer letters only isolated paragraphs have been included. Use of italics in the letters was not entirely consistent and has been reproduced as used by Prof. Hering. Selection of the letters has been based primarily on their entomolo gical interest but numerous passages have also been included illustra ting in some way Hering's personal qualities.

My association with Prof. Hering extends over the past seventeen years, and during this period I have visited him at his home on more than forty occasions and received over 300 letters from him. These letters contain much detailed entomological information. They also throw considerable light on Prof. Hering's personality and character and the background against which he worked. The publication of at least part of these letters as a final tribute to Prof. Hering has been in my mind for many years. This original idea has now been somewhat extended by the inclusion of a number ofletters to Dr. H. Buhr, Dr. J. Klimesch, Dr. F. Groschke and G. C. D. Griffiths, all of whom shared Prof. Hering's interest in leaf-miners. Although Dr. Buhr is primarily a botanist, with Hering's encour agement he has taken an active interest in leaf-miners throughout his career and his remarkable collecting becomes apparent from Hering's letters to him. For many years Prof. Hering has written between two and three thousand letters annually. It has obviously been possible to consider here only a very small proportion of these. From many of the longer letters only isolated paragraphs have been included. Use of italics in the letters was not entirely consistent and has been reproduced as used by Prof. Hering. Selection of the letters has been based primarily on their entomolo gical interest but numerous passages have also been included illustra ting in some way Hering's personal qualities.

Phytophagous insects represent a very particular not really belong to their host plant range. This may group of organisms. Firstly, their number amounts lead to mistaken conclusions especially in regions to more than one quarter of all recent species (ex where only few observations were possible, as well cluding fungi, algae and microbes) and together with as in the case of uncommon insect species. Fourthly, the green plants on which they feed they form al the great majority (99. 4%) of the agromyzid species most one half of all living species described so far. studied show a high degree of host specialization Secondly, their overwhelming majority shows very which makes these insects especially suitable for narrow host plant specialization, that is they feed taxonomic-phylogenetic considerations. only on one or a few, mostly closely related plant With such an enormous amount of data, it may species, a characteristic that led J. H. Fabre to elab have been tempting to draw far-reaching conclu orate the notion of the 'insects' botanical instinct' a sions. However, the author has been very careful in century ago. doing this.

The print edition is available as a set of two volumes (9788787491082).

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 to 313 today. He is thus uniquely qualified to write this book about the hundred and fifty or so species which are regularly associated with cultivated plants. Much of the taxonomic detail provided here will be of value primarily to specialists; but with the help of a microscope and the botanical host list (Chapter 2) and the numerous illustrations (mostly prepared by ANN SPENCER) those in agri cultural institutes and elsewhere should now be able to identify the majority of species found attacking crops in any part of the world.