452 ‘THE FERTILISATION OF FLOWERS. [PART III, 
again narrows suddenly, and a little more than 1 mm. from its 
upper end two sharp processes of the hood (g, 1, 2) almost meet 
in the middle and divide the entrance into a very small upper and 
a long lower part. Through the upper opening protrudes the — 
style, which springing from the bilocular ovary lies close to the 
posterior wall of the corolla, and curves sharply downwards near — 
its anterior end to bear the capitate stigma; the long, lower 
opening admits the bee’s head. So long as this slit is only 1 to 2 
mm. broad, viz., from the insertion of the under lip to the wider 
part above, its edges are very markedly rolled outwards, and that 
part of the inner wall of the corolla which is brought by this 
evolution of the edge to form the margin of the narrow slit is 
closely set with sharp points (d, 1, 2, 4), while the wider portion 
(ce, 1) has smooth edges. There is also on each side of the upper 
lip a reddish thickened band (h, 2), which begins on a level with 
the wide part of the slit at the upper end of the evoluted edges 
(e), and forming a sharp angle with the ridge runs backwards and © 
downwards to disappear on a level with the base of the under lip. 
What have all these characters, the compressed base of the 
under lip, the oblique position of its three-lobed lamina, the 
evoluted edge of the narrow entrance, its rough edges, the sudden 
enlargement with its smooth edges, the red stripes at the sides — 
of the upper lip, to do with fertilisation by humble-bees? Are 
they accidents to be neglected, as is done by Hildebrand in his — 
figures in the Botanische Zeitung (1866, pl. iv.) and by Dr. Ogle 
in the Popular Science Review (Jan. 1870)? Careful observation 
of an insect visiting the flower makes me think otherwise. The 
bee comes flying along with outstretched proboscis, and avoiding 
the toothed edges of the slit, thrusts its proboscis at once in 
alighting into the widest part of the opening (e, 1); the upper part 
of its head then touches the stigma, which stands scarcely 2 mm. 
above the wide part of the opening, and the oblique position 
of the lower lip causes the bee’s head also to be placed obliquely ; 
its forefeet grasp the basal part of the lower lip, its middle pair 
of feet grasp the tube of the flower on a level with the lower lip, 
and the hindfeet rest upon leaves or other flowers below. Standing 
in this position, the bee applies its head, which is 24 to 3 mm. 
thick and 5 mm. broad, to the (4 mm.) wide part of the entrance, 
with just so much obliquity as gives it the best chance of entering. 
And now the edges of the slit, rolled outwards and thereby stiffened 
(d, 1,2), and the bands on the upper lip (A, 2), play their part. - 
Joining above at a sharp angle, they bound, on each side of the— 
