FLOWERS AND INSECTS. XVIII. 
CHARLES ROBERTSON, 
_ Acra&a L.— A. spicata L. is a white pollen-flower with incom- 
plete proterogyny, though Axell regarded it as homogamous. 
Dr. Buddeberg’s observation at Nassau of the visits of Byturus 
fumatus F (Dermestidz) and Forficula auricularia L.(Orthoptera) 
hardly indicates more than partial investigation or unfavorable 
conditions (4). 
Acr#a aLBa Bigel.— This agrees with observations made on 
A. spicata, of which it has been regarded as a mere variety. 
The plant is rather rare, in low rich woods, rising 4-5°" 
and bearing short racemes. The sepals fall when the flower 
opens. The numerous stamens and the stigma are white and 
are the most conspicuous parts, the slender petals being of little 
use. The ovary is surmounted by large two-lobed stigma, 
Which is receptive before the anthers open. The stamens are 
turned to a more or less horizontal position, so that, after the 
anthers open, the insect visitors are likely to touch the stigma 
before being dusted with pollen. The flowers open almost 
Simultaneously. The proterogyny is incomplete, nectar is want- 
ngs and the insects abandon the flowers as soon as the pollen 
'S Zone, 
From their white color, small size and nectarless condition, 
> ein seem depend upon the females of small species 
ing ae by which they are abundantly visited. The bloom- 
: son is from May 3 to 23,a plant found in bloom on pune 
~ eeming quite an exceptional case. On May 8 the following 
“sitors were observed : 
hee Andrenidae ; (1) Andrena sp. 9, ¢. p. 2; @) eT see 
Rob, 9, a ab.; (3) H. zephyrus Sm. 9, c. p.; (4) Augochlora co 
— the pollination of Actza see : 
229 
