136 INTRODUCTION 
Veronica Chamaedrys will serve as a typical example. ©The bright blue flowers 
are streaked with darker lines, and ornamented in the middle with a paler nectar- 
guide. They are united into moderately conspicuous inflorescences, and are 
homogamous. The style with its terminal stigma projects obliquely downwards 
Fic. 51. Veronica latifolia, L., a Hover-fly Flower. A. Flower seen exactly from the front (x 7), 
B. The same seen from the side, after half of it has been removed (x 7): s, sepals; Z, petals; 7, nectary; 
a, stamens; S¢, stigma. 
out of the middle of the flower where nectar is produced, while the two stamens 
diverge from each other to right and left. The filaments are narrowed at their 
bases and can therefore be easily turned inwards. Small variegated Syrphidae 
Fic. 52. Cirvcaea lutetiana, L., a Hover-fly 
Flower. The flower is seen obliquely from above. 
a, ovary; 5, sepals; c, petals; d, stamens; ¢, style 
with stigma. 
(Ascia podagrica, Melanostoma mellina, and 
others) first hover for a second in front of the 
flower, delighting in its beautiful colour, and 
then settle on its centre, thus coming into 
contact with the projecting stigma. In order 
to obtain a firm hold, they first grasp the 
filaments with their fore-legs, and immediately 
afterwards with their middle and _ hind-legs, 
and before one has time to see it they have 
unconsciously brought together the two stamens 
under the ventral side of the abdomen, and 
dusted that region with pollen, which is de- 
posited on the stigma of the next flower they 
visit (Fig. 50). 
This striking floral mechanism also occurs 
in a few other species of the genus Veronica, 
though in some of them it is not so highly 
perfected, e.g. V. longifolia, montana, latifolia 
(=urticifolia). (See Fig. 51.) 
Our native species of Circaea present the same adaptation to hover-flies, for 
it is only insects of this kind that bring their floral mechanism into action in the 
proper way. 
