Lhe Problem of Adaptation II 
“As soon as this has taken place the anthers, which have 
been closed hitherto, dehisc and become freely accessible,” 
as a result in the change in the stigma and of the collapse 
of the hairs at the base of the enlargement which has 
widened. The fly can now crawl under the anthers, and, 
Fic. 1.— The fertilization of Aristolochia Clematitis. A, portion of stem with 
flowers in axil of leaf in different stages. B, longitudinal sections of two 
flowers, before and after fertilization. (After Sachs.) 
if it does so, new pollen may stick to its back. At this 
time the hairs in the throat dry up, and the fly can leave 
its prison house, Figure 1 C. If the fly now enters another 
flower this is fertilized by repeating the process. The unfer- 
tilized flowers stand erect with widely open mouths. As soon 
as ‘they have been fertilized they bend down, as seen in 
