PART III. 
THE MECHANISMS OF FLOWERS. 
In this section I propose to discuss such questions as the following, in 
regard to a number of native or commonly cultivated plants. By what insects 
is each visited? What does the insect come in quest of, and how does it 
behave? In what manner does it effect transference of the pollen? What 
peculiarities of the flower have special relation to the particular visitors ? 
What special peculiarities of the flower aid cross-fertilisation in case of insect-_ 
visits? In absence of insects, can self-fertilisation take place, and to what 
extent does it actually occur ? 
There are few instances in which I am in a position to answer all these 
questions. In some cases I have studied the structure of the flower but 
have never had an opportunity of observing its insect-visitors ; in other cases 
I have noted insect-visitors without studying closely the mechanism of the 
flower. . 
In choosing my figures I have taken account of those already existing. 
In many cases I have omitted to figure flowers which happen to be well 
illustrated in the works of Sprengel, Darwin, or Hildebrand (e.g. Aristolochia 
Clematidis, Viola tricolor) ; in other cases I have selected a different species 
of the genus (e.g. Iris, Polygala). And in most cases I have passed over with 
a few words flowers which have been described elsewhere in great detail, 
unless I had to correct or amplify the previous accounts. . 
Professor Schenck of Weilburg has checked my identifications of the greater 
part of my bees, wasps, and sand-wasps (/fossores) ; Mr. Frederick Smith has 
compared all my species of bees, wasps, and sand-wasps with the collection in 
the British Museum (which includes Kirby’s type-specimens) ; Dr. Speyer of 
Rhoden has placed my determinations of Lepidoptera beyond dispute, and 
Herr Winnertz of Crefeld has identified those Diptera concerning which I 
remained doubtful. Herr Borgstette, jun., of Teklenburg, has sent me numerous 
insects collected upon flowers in his neighbourhood, along with accurate 
records of the plant on which each specimen was obtained. 
Contractions employed in the Lists of Insects. 
l.h.=licking honey ; s.=sucking ; ¢.p.=collecting pollen ; f.p,.=feeding 
on pollen ; cor.=corolla; ab. abundant, 
Se 
