154 ENTOMOLOGICAL NEWS. [April, ’o8 
across the projecting point of the stigma. In flava especially, 
egress is exceedingly difficult except at the five entrance holes; 
and all of the numerous insects observed visiting these flow- 
ers emerged after considerable struggling through one of 
these orifices, almost invariably again scraping the stigma in 
their departure. In flava therefore, with its heavy closely- 
overlapped petals usually preventing the escape of the visit- 
ing insects except by repassing the stigma, some special pro- 
vision for preventing habitual self-pollination by insect ag- 
ency would be expected; and this seems to be provided for in 
the position the flower assumes upon its stem at various ages. 
When the bud first appears above the ground it is borne up- 
right upon the stem; as the blooming period draws near, the 
stem bends just below the bud, making a complete turn, so 
that when the flower opens the style occupies the position 
of an inverted umbrella, catching and retaining the falling 
pollen, most of which is shed within twenty-four hours after 
the flower begins to open. The flower then begins again to 
change its position, often being very noticeably tilted on the 
stem by the third day, and eventually, long before the fall of 
the petals, it takes a position at right angles to the original 
one. These changes of position and the structure of the flower 
are shown on Plate IX. The tilted and finally upright flow- 
ers naturally retain less pollen than the newly opened horizon- 
tal ones, and often the tilted flowers show little trace remain- 
ing of the abundant supply in the newly-opened blooms. As 
the blossoms remain fresh and continue to be attractive to 
insects for more than two weeks, it would seem that this 
change in the position of the flower and the consequent spill- 
ing of the pollen decidedly favor cross-fertilization. 
Ants are almost invariably present in the flowers, attracted 
by the abundant nectar oozing from the ovary, but they are 
probably of little importance as pollenizers. The ant most 
abundant in fava at Summerville is identified by Prof. W. M. 
Wheeler as Tapinoma pruinosa Roger. Ants, wasps, and oc- 
casionally butterflies visit the outside of the flower; spiders, 
