3 82 
The Ohio Naturalist. 
[Vol. XI, No. 8, 
of the nectar pockets arises a curved horn-shaped process that 
bends inwards over the stigmatic disc. 
“An insect searching for nectar slips about on the smooth 
flowers which make up the umbel until its feet get a firm hold in 
the lower part of a slit. When it wishes to go and draws up the 
leg the claws are guided upwards in the slit so that the clip becomes 
attached to the foot. During the subsequent movements the 
pollinia are introduced into one of the slits of another flower, and 
effect cross-pollination, while at the same time another clip affixes 
itself. 
The development of the pollinia was investigated by Corry. 
He also found that flowers are infertile not only with their own 
pollen, but also with that from plants raised vegetatively from 
the same stock. Pollination is fully effective only when it takes 
place between flowers belonging to plants grown from the seeds of 
different stocks. Stadler worked out the histological details of 
the secretion of nectar and found that this is produced, not only 
in the petaloid cuculli, but also by internal nectaries on the inner 
wall of the stigmatic chamber. The approximated lower edges 
of the slits serve as nectar-covers for the latter . 7 
The fact of the plants being infertile to their own pollen as 
well as to pollen from plants raised vegetatively from the same 
stock probably explains the small number of fertile pods observed 
later in the season as compared with the large number of flowers 
originally observed. 
Visitors: Diptera; Pollenia rudis, Lucilla caesar, Chrysopus 
moereus; Lepidoptera; Harrisina americana; Hy- 
menoptera; Microbembex monodonta. 
Asclepias incarnata (Swamp Milkweed). 
Visitors: Diptera; Pelcteria robusta, Midas calvatus, Phor- 
mia regina, Lucilia sericata, Phthiria sulphurea; 
Lepidoptera; Anosia plexippus, Satyrodes eury- 
dice, Argynnis cybele; Coleoptera; Donacia pusilla 
Hymenoptera; Microbembex monodonta. 
Asclepias tuberosa (Butterfly-weed). 
Visitors: Lepidoptera; Harrisina americana , Anosia plex- 
ippus; Hymenoptera; Microbembex monodonta, 
Xylocopa virginica. 
Bignoniaceae (Bignonia Family). 
Tecoma radicans. In making collections on this plant it was 
found that most of the visitors had little to do with pollination 
but were busy collecting some material from the calyx. The nectar, 
which is secreted at the base of the long corolla-tube is availa- 
ble to certain insects only. The arrangement of the stamens 
7 Op. cit., III. 93-94. 
