AUTHOR’S PREFACE Xi 
of the way in which the visit is effected is frequently not sufficiently 
detailed. There is often a similar lack of detail with regard to the 
numbers of visitors to a species and the constancy of their visits. This, 
however, is due to the fact that the authors whose observations are 
embodied have not given particulars. In this handbook an attempt is 
made to give a relatively complete account of visitors to the various 
species of plants, so as to determine their circle of guests, and therefore 
all records, however imperfect, are cited. For the most part, however, 
the kind of activity, and the numbers and constancy of the insect visitors, 
are indicated by the following contractions :—‘skg.’ (sucking), ‘nect-lkg.’ 
(nectar-licking), ‘ po-cltg.’ (pollen-collecting), ‘ po-dvg.’ (pollen-devouring), 
and ‘freq.’ (frequent). From these symbols one may almost always recognize 
distinctly whether the visitors were acting as pollinators or not, and a more 
exhaustive account of the behaviour of the insects during their visits to 
flowers of simple structure is therefore, in most cases, quite unnecessary. 
Moreover, it would greatly add to the size of this already voluminous work. 
Such details have only been given in the case of flowers with distinctly 
complicated adaptations of the floral leaves, where a more exhaustive 
description of the relations seemed necessary. An effort has been made 
to arrange the observations according to the geographical position of the 
districts in which they were made, though this could not always be 
carried out consistently. 
In naming and arranging the insects I have made use of the following 
works.— 
C. G. DE DALLA TORRE. Catalogus Hymenopterorum hucusque descr. syst. et 
syn. Leipzig, 1892 on. (So far as published.) 
J. R. SCHINER. Fauna Austriaca. Die Fliegen (Diptera). 2 Bde. Wien, 1862 and 
1864. JOS. MIK, Verzeichnis der Arten-Namen, welche in SCHINER’S Fauna 
Austrica enthalten sind. Wien, 1887. 
A. PuToN. Catalogue d’Hémiptéres de la Faune paléarctique. 3° éd. Caen, 1886. 
C. BRUNNER V. WATTENWYL. Prodromus der europdischen Orthopteren. Leipzig, 
1882. 
G. SEIDLITZ. Fauna baltica. Die Kafer der deutschen Ostseeprovinzen Russlands. 
2. Aufl, Kénigsberg, 1891. (Where this work did not suffice the two following 
were used.) 
G. SEIDLITZ. Fauna transsilvanica. Die Kafer Siebenbiirgens. Ké6nigsberg, 1887. 
M. GEMMINGER et B. DE HAROLD. Catalogus Coleopterorum hucusque descriptorum 
synonymicus et systematus. Miinchen, 1868-76. 
O. STAUDINGER und M. WocKkE. Katalog der Lepidopteren des europdischen 
Faunengebietes. Dresden, 1871. 
M. Rostock. Neuroptera germanica. Zwickau, 1888. 
The visitors of flowers are arranged alphabetically in orders, families, 
genera, and species. A revision of the insects observed by me visiting 
flowers, as detailed in earlier writings, has been undertaken by the fol- 
lowing :—D. Alfken, Bremen; A. Costa, Naples; F. Dahl, Kiel; V. von 
