viii AUTHOR'S PREFACE 



Boeken,Verhandlingen,enz. omtrent de bevruchting der Bloemen,van 1 883 tot 

 1889 verschenen ' (Bot Jaarb. Dodonaea, Ghent, ii, 1890, pp. 195-254) ; and 

 lastly, the ' Litteraturverzeichniss (1883-93)' in Loew's ' Bliitenbiologische 

 Floristik' (Stuttgart, 1894, pp. 4-18). I have supplemented these notices 

 of the literature especially by working through the references published 

 by V. Dalla Torre in Just's 'Botanischer Jahresbericht ' from 1883 to 1895, 

 and placed at my disposal by the author, and also the ' Neue Litteratur ' 

 in the 'Botanisches Centralblatt ' from 1880 till October i, 1897. An 

 appendix gives the works on flower pollination that have appeared during 

 the printing of the first volume, up to April, 1898. Here also are named 

 a few of the oldest works on the sexuality and the fertilization of flowers, 

 which I had at first overlooked, as well as the literature on perception 

 of form and colour, and on the olfactory and visual powers of insects, 

 mostly from H. J. Kolbe's ' Einfiihrung in die Kenntnis der Insekten ' 

 (Berlin, 1893). The bibliography as here presented should be moderately 

 complete, but I cannot in every case vouch that the titles are absolutely 

 correct, as the original works were not always available, and some of 

 the sources on which I had to depend contain numerous printers' errors. 



The works that appeared during the preparation and the printing of 

 this handbook have been, as I have already said, taken into consideration 

 as far as possible. The notices which J. Behrens has published on 

 Kolreuter (Verh. Natw.Ver., Karlsruhe, 1894), and the important investiga- 

 tions of F. Plateau which have been published under the title ' Comment 

 les fleurs attirent les insectes' (Bui. Acad, roy., Bruxelles, 1895-7), are 

 discussed in an appendix to the introduction. 



The second volume contains descriptions of the structure of flowers, 

 and notices of the flower visitors hitherto observed in Europe and in the 

 Arctic regions, and of their relations with the flowers they visit, following 

 closely the accounts of the observers who first described the facts. I have, 

 in particular, left unaltered, so far as possible, Hermann Miiller's descrip- 

 tions of flowers, as an account by this investigator cannot be safely 

 modified: I have, however, usually made slight abbreviations. While 

 descriptions of the structure of flowers belonging to indigenous European 

 species have generally been retained intact, and their visitors given as 

 fully as possible, I have only briefly indicated observations made in 

 Europe on cultivated but non-indigenous plants. A fuller description 

 will be given of these in the third volume of this work, but they could 

 not be altogether omitted in the second, as it was impossible to distinguish 

 sharply between indigenous, acclimatized, and cultivated species. I have, 

 therefore, given short accounts of all observations made in Europe on 

 plants that are not indigenous. On the other hand, I have left unnoticed 

 all investigations which, though described in European periodicals, refer 

 to extra-European regions. It is obvious that in dealing with such an 



