ABSTRACT
WE were interested, in the first place, in insects of every kind. Entomologists, however, have to deal with a class more numerous than all other living things put t9gether. For insects are the dominant form of animal life on.the earth. At a conservative estimate about half a million distinct kinds are known and vast numbers still await discovery. Nevertheless most people are quite unaware of the existence of the great majority of the creatures we were seeking; forms usually inconspicuous, often dull-coloured and with hidden ways of life; mostly small or minute, even as minute as one millimetre (about lath inch) long. Thus in practice we could not collect all orders of insects equally. Attention was therefore concentrated on the groups most likely to throw' light on questions of geographical distribution. Such, in particular, are grasshoppers and locusts, beetles-especially certain groups associated with particular plants or restricted to very high altitudes-bees, wasps and related forms, as well as butterflies and moths.
