596 THE FERTILISATION OF FLOWERS. [PART IV. 
insects this power seems only to have arisen with the habit of 
visiting flowers, and to have increased pari passw with the taste 
for flowers and with the length of the proboscis. On the whole 
we find red, violet, and blue colours appearing for the first time 
in flowers whose honey is quite concealed and which are visited 
by more or less long-tongued insects (bees, long-tongued flies, 
Lepidoptera), or else in flowers visited for the sake of their pollen 
chiefly by bees and: drone-flies (Hepatica triloba, Verbascum 
pheniweun). 
The forms, colours, and odours of the flowers in a particular 
region must depend in the closest manner upon the insect fauna 
of the region, and especially upon the relative abundance in it of 
the various classes of insects. This conclusion is in complete 
accordance with the following comparison of my observations on 
the Alps and in North Germany. On the Alps, Hymenoptera and 
especially bees are relatively much less numerous and Lepidoptera 
much more numerous than in Low Germany. 
I have observed upon flowers :— 
1. In Low Ganuany.| * Ohman, | OR TREES, 
Gt Inooota.| obbaryed. [ot Ingocta | dbecrved. of Ineoets. | Sbabewed 
Coleoptera. ... 129 469 83 337 33 134 
Diptera 253 1,598 348 1,856 210 930 
Hymenoptera 368 | 2,750 188 §| 1,382 88 519 
(Apide) (205) | (2,191) | (120) | (1,141) | (49) | (402) 
Lepidoptera 79 | 865 | 220 | 2,122 | 148 | 1,190 
Other Insects 14 49 7 15 3 6 
TOTAL... 843 5,231 841 5,712 482 2,779 
