CERTAIN SPECIES OF ASCLEPIADEZ. 53 
bination was originally greater. From these, four pollen-masses 
had been detached, eight still remaining attached to the glands. 
In another instance four glands were attached together, from 
which six pollen-masses had been removed, two only remaining 
attached to the unremoved gland. In this case also an arm was 
left disruptured in the upper gland, showing that the combination 
had been formerly larger. 
Towards the close of their flowering-season a careful examina- 
tion of these plants would probably result in many more curious 
combinations. 
As an illustration of the probable correctness of this species 
not being fertilized by the tarsi, I have never met with a gland 
attached by itself to the tarsus; yet in most cases the presence 
of a disruptured arm would show that one gland at least remains 
attached. 
When the Pallosoma visits these flowers, as I have frequently 
observed, it plunges its head in between the middle lobes of the 
folioles to their base, busily sucking the nectar; but in so doing 
the smaller lobes, projecting upwards, interfere with it in some mea- 
sure, and, as I have noticed, caused considerable annoyance to the 
insect. To this and the exciting influence of the nectar I, in some 
measure, attribute its restlessness; although it is, apart from these, 
an active and watchful insect. I have also noticed that it some- 
times sucks round the gland itself; and as Robert Brown states that 
the gland, in the species which he examined, continues to secrete 
after the opening of the flower, I am disposed to think that this 
secretion may be of essential service to the flower in attracting 
the wasps when the more abundant store of nectar at the base of 
the folioles is exhausted. 
It is probable, too, that the adherence of so bulky an object as 
any of the combinations already mentioned to any part of the 
bead would cause much discomfort to so agile an insect, to release 
itself from which the fissures of the anthers offer a ready means. 
The attentions of this insect are paid to several other Ascle- 
piads, such as Periglossum, as also to a Cissus and a Eucomis. 
These flowers are, most of them, dull-coloured and of very different 
size, but afford, apparently, a quality of nectar peculiarly pleas- 
ing to this wasp; for there were in blossom at the same time Ascle- 
piads quite as conspicuous and more so than Periglossum, affording, 
too, an abundance of nectar, but which I have never seen it visit, 
although they appeared attractive to some other Hymenoptera. 
