150 THE FERTILISATION OF FLOWERS. [PART IT. 
purple petals to a diameter of 30 to 40 mm., and turn towards the ~ 
sun, so that, being brightly illuminated, they are visible at a great — 
distance. ) 
The darker lines which converge to the centre, and the pale- 
coloured claws of the petals, serve to direct insects towards the 
honey, which is secreted by five glands at the bases of the outer 
stamens, and protected from rain by hairs at the bases of the — 
petals; it is accessible to very short-lipped insects. Insect-visits — 
are so frequent that the power of self-fertilisation has become 
completely lost. Each flower passes through three well-marked ~ 
stages, in which first the five outer stamens, next the five inner 
stamens, and thirdly, when these have withered, the five stigmas, 
become in turn ripe and stand up prominently in the middle of 
the flower. Each whorl of stamens bends outwards as its anthers — 
wither. hehe 
Near Lippstadt this plant is confined to a single locality, 
and I have only once watched it, for about half an hour, in a light 
east wind and changeable sky (August 21, 1871). I was convinced — 
in this short time of the great number of insects which frequent — 
the plant. Whenever the sun shone out, I found the flowers visited — 
by numerous flies and bees, especially species of LHalictus. 
A. Hymenoptera-—A pide; (1) Halictus cylindricus, F. ¢; (2) H. albipes, 
F.¢; (3) H. flavipes, F. ¢; (4) H. longulus, Sm. 9; (5) H. nitidiusculus, — 
K.? ¢; (6) H. zonulus, Sm. ¢; (7) Andrena dorsata, K.¢; (8) A. fulvicrus, — 
K. ¢; (9) Prosopis communis, Nyl. 9. B. Diptera—(a) Syrphide: (10) — 
Rhingia rostrata, L. ; (11) Melithreptus scriptus, L. ; (12) Eristalis tenax, L. ; ‘ 
(13) Helophilus pendulus, L. ; (14) Platycheirus peltatus, Mgn. ; (b) Muscidae : 
(15) small species of Anthomyia. C. Lepidoptera—(16) Pieris rape, L., 
—all sucking. _@ 
77. GERANIUM PRATENSE, L.—This is generally the most conspi- — 
cuous and most abundantly visited plant in the meadows where it — 
grows, just as G. palustre is in the marshes. It agrees in structure — 
for the most part with the former species, and like it has lost 
the power of self-fertilisation. Hildebrand gives (351, p. 19) — 
a drawing and short description of its markedly proterandrous 
flowers. He has shown that, at the time when the anthers dehisce © 
and are bent over the stigmas, these latter as a rule are incapable — 
of fertilisation; they become capable ‘of fertilisation when the 
anthers have diverged away from them, and finally lose this 
capability on the falling off of the petals (342.) 
Visitors: A. Hymenoptera—Apide: (1) Apis mellifica, L. §, very ab., s. ; 
(2) Osmia rufa, L. 9,8. (May 27, 1868) ; (3) Chelostoma nigricorne, L. 9, s. 
