52 MR. J. P. M. WEALE ON THE FERTILIZATION OF 
On the wasp already mentioned I have found pollen-masses at- 
tached to the tarsi, to the long hairs of the sternum and coxe, 
and to the spines of the leg; but I have never found more than 
a single pair thus attached, and have never found glands separated 
from their masses. 
On the other hand, it is by no means uncommon to find 
several combinations of the glands attached to the unremoved 
pollen-masses, as also to those inserted in the fissures of the an- 
there. I once found and figured a portion of the head of an 
insect attached to a pollen-mass, but I unfortunately lost it 
in removing it from the pollen-mass to which it was fixed. 
I have twice observed these wasps with several pollen-masses 
attached to some portion of the head, but failed in capturing 
the specimens. I noted this especially as occurring on the 
23rd of January of this year, when I observed numbers of 
these wasps frequenting the plants. I am myself thoroughly 
convinced of the correctness of this view, as without it there 
ean be no explanation of the structure of these plants. I 
have repeatedly watched wasps with the pollen-masses attached 
to their tarsi; and although they have visited many flowers, I 
have in no instance seen the masses inserted, although it is not 
uncommon to see them thus withdrawn. Although numbers 
of pairs of pollinia are withdrawn, very few in comparison are 
inserted. 
I have already stated that in Gomphocarpus fruticosus the pol- 
len-masses close together inwardly on withdrawal, so as to clasp 
tightly the leg of the insect. 
In this species there is a similar movement, only in a slighter 
degree. The arms bend inwardly, so that the two pollen-masses 
are nearly parallel, but somewhat apart from each other. 
I have not ascertained the structure which produces these and 
other movements in the pollen-masses of Asclepiads, as, owing to 
their diminutive size, they require close and careful examination, 
for which I have not had sufficient leisure. 
It is a curious matter for observation that in some Asclepiads 
this movement never takes place, in some only slightly, while 
in others, as in Periglossum and Aspidoglossum, the movement 
takes place in an entirely different direction. 
In this species I have found most curious combinations of the 
pollen-masses. I-have seen five glands attached together, in the 
first of which an arm was still inserted, showing that the com- 
