150 THE POLLINATION OF SATYRIUM BICALLOSUM, THUNB. 
in which I observed recently opened flowers with only one pollinium removed. 
In most species of Satyrium, the three sepals and the two lateral petals form 
a median resting place for insects, and there is only a single entrance to the 
flower. In this type, the simultaneous removal of the pollinia is possible. In 
S. bicallosum, each entrance to the flower has an alighting place formed of a 
lateral petal and a lateral sepal (Fig. 7), and each aperture leads almost 
directly into one of the two short saccate spurs of the galea. In the specimens 
studied by me, the flowers were of a dull greenish-yellow colour, but on the galea, 
and just above the spurs, there were lurid purple spots, one above each spur; 
this coloration often extended to the spurs themselves. When viewed from 
the front, the two purple “eyes” in the depths of the flower have a striking 
appearance, and no doubt form one of the features attractive to insects. The 
dull yellow and purple coloration, uncommon in Satyrium, but found in a 
few species such as S. pumilum, Thunb. and S. Lindleyanum, Bolus, indicate 
a fly pollinated flower; such coloration being frequent in Stapelia and other 
fly flowers. I was unable to detect any scent however. 
The column itself is of an unusual type. Instead of being slender and 
arcuate, as in most Satyria, it is very short and condensed, and almost hidden 
from view behind the depressed apex of the galea (Fig. 7). 
The stigmatic. lobe of the column is formed of two curved, finger-like 
processes, directed towards the front of the flower; immediately underneath 
the processes, the stigmatic surface is situated (Figs. 1 and 2). The finger-like 
processes are depressed to such an extent that the stigmatic surface is almost 
divided into two lateral portions, each one abutting upon the adjacent passage 
leading to the spur (Fig. 6). These surfaces are viscid when receptive, and that 
they are definitely stigmatic is proved by the ease with which I was able to 
germinate the pollen masses upon them. I also observed the very numerous 
pollen tubes penetrating the tissues. Many flowers were examined in which 
pollen had been placed on the stigma by insect agency, and in these cases the 
pollen grains had also germinated. 
The anther is of the usual type in Satyrium, but, as Dr Bolus notes, the 
entire anther is tilted upwards in such a fashion that the two viscid discs are 
directed towards the back of the flower. 
The adhesive disc of each pollinium, however, projects somewhat laterally 
into the adjacent passage to the spur (Fig. 6). When mature the pollinia lie 
rather loosely in the anther cells, and are easily removed. Each pollinium 
consists of from 40 to 50 massulae, loosely held together, the entire mass being 
pear-shaped, and cleft almost into two portions (Fig. 4). The caudicle is 
rather short, and the adhesive disc circular. Just below each anther lobe is 
a white callosity, composed of a mass of cells which disintegrate, soon after 
the flower opens, to form a fluid mass. These callosities are considered to be 
rudimentary stamens. They probably do not function at any time as food 
