xx, 436 pp., 16 col + 6 b/w plates, endpaper maps, Vg in d/w, with colour illustration mounted to front panel (minor scratch to mounted illustration; in clear, removable protective sleeve). Some browning to endpapers. This book is based on surveys carried out by the author in 1931-2 and 1947. More than 360 are described, and 101 species illustrated in colour. [47199]