38 DR. G. KING ON THE GENUS FICUS. 
is a matter on which I cannot pretend at present to throw any 
light; I shall only state the problem. The males are shut up 
from an early age with a number of females, the structure of 
whose organs is unfavourable to pollenization. No pollen is 
produced by the males that are shut up with these females until 
- all possibility of their becoming fertile with pollen has been pre- 
cluded by the encystment within each of their ovarial cavities of 
the pupa of an insect. On the other hand, a number of perfectly 
formed females, all well adapted for the reception of pollen, are 
shut up together in a receptacle which contains neither male nor 
gall-flowers, and to which it is from a very early stage impossible 
for pollen-bearing insects to get access. Yet each of the females 
situated in such apparently disadvantageous circumstances bears 
a well-formed embryo, which develops into a perfect seed. 
This arrangement, by which the receptacles are practically 
diecious, obtains, as I have said, in a large proportion of 
the species of Ficus. There is, however, a group of species 
(Urostigma) in which it does not obtain, and in which male, 
fertile female, and gall-flowers are contained in the same recep- 
tacle. In this group the difference in structure in the early 
stages between gall and fertile female flowers is very slight, and 
in some cases I could find no difference whatever. And even: 
the ripe achenes of the fertile females are in many cases undis- 
tinguishable externally from the ovaries containing far advanced 
pups, and it is only by cutting them open that they can be 
recognized. As regards the relation in this group of Urostigma 
of the male flowers to the fertile female and gall-flowers, there 
are two types of arrangement. In one set of species (of which 
F. bengalensis and F. tomentosa are good examples) the male 
flowers are comparatively few in number, and are confined to & 
zone at the apex of the receptacle, just under the ostiolar scales ; 
while in another set the male flowers are intermixed with the 
fertile female and gall-flowers over the whole surface of the 
interior of the receptacle. 
A third small group (Synæcia) has neuter flowers mixed with 
the fertile females in one set of receptacles; while the other set 
of receptacles contain only male and gall-flowers. A fourth 
group (for which I propose the name Paleomorphe) has male 
flowers which, in addition to an anther, contain an insect-attacked 
or gall-pistil. These pseudo-hermaphrodite flowers are confined 
to the subostiolar zone, the remainder of the receptacle being 
