268 THE FERTILISATION OF FLOWERS. [PART IIT, — 
back of the insect-visitor. Delpino has observed humble-bees and 4 
Xylocopa violacea accomplishing cross-fertilisation in this manner. 
(172). 
divided by rings of hairs into three chambers, the lowest of which 
contains the honey. From the size of the flowers, and their rich 
store of honey, Delpino imagines that humming-birds are the 
fertilisers; and he supposes that the triple fence serves to keep 
away less intelligent visitors (178). 
My brother Fritz Miller has observed in his garden at Itajahy 
that some Passifloree are fertilised exclusively or chiefly by hum- 
ming-birds; but he is convinced that abundance of honey is no 
proof of the flower being visited by humming-birds, ‘for one 
species in his garden, which is very diligently visited by them, 
contains no honey and is odourless, while another smaller white ~ 
species flowering in Itajahy, in spite of great abundance of honey 
and a pleasant scent, is never visited by humming-birds. The — 
numerous corone, projecting ledges, etc., seem to him to be of 
service in detaining small insects in the lowest chamber (which 
often contains no honey) and keeping them caged for the hum- — 
ming-birds, rather than in making access to the chamber difficult 
for unprofitable visitors of low intelligence. 
Orv. CUCURBITACEZ. 
171. Bryonta pioica, L,—The lower part of the calyx and 
corolla, both in the male flowers and in the female flowers (which 
are only half as large) is adherent to a hemispherical cup-shaped 
disk, whose naked, fleshy floor secretes honey. In the male flower 
five irregularly formed fleshy stamens arise on the edge of this cup, 
and are so expanded and inclined inwards that they completely — 
roof in the cup. Four of the anthers cohere, to form two pairs ; 
the fifth is free on both sides. Thus the honey-holding cup has 
three narrow lateral entrances each placed between two stamens 
and fringed with long hairs; and also an entrance from above in the 
midst of the upper ends of the stamens. The anthers form narrow 
ridges on the broad stamens, and the long, narrow slits by 
which they dehisce are so bent that the greater part of each 
faces one of the lateral openings, while the uppermost portion 
looks directly upwards. A honey-seeking insect alighting in the 
middle of the flower may thrust its proboscis down in the midst of 
all the stamens, or approaching from the side it may reach the 
In Passiflora racemosa, Brot. (P. princeps, Lodd.), the tube is : 
ion 
Ba 
Ea EINE 
46 omy he ee 
