Charles Darwin read a remarkable paper on the sexual 
forms of Catasetum, a genus of the Orchidaceae charac- 
terized by extraordinary dimorphism. In the same year 
his classic treatise on the relation between insects and or- 
chids appeared. This comprehensive work, spiced with 
conjecture, gave the results of patient observation and 
not only banished all doubt regarding the function of the 
pollinia, but centered the attention of naturalists on the 
complex symbiosis existing between orchids and food- 
seeking insects. Since Darwin’s treatise on orchid-polli- 
nation was published, there have been many contributions 
to the subject, but these have been scattered in various 
journals and have to do for the most part with single 
species. 
One would be justified in concluding that the exam- 
ples of pollination as Darwin described them for Catase- 
tum and Coryanthes constitute the most complicated 
symbiotic relationships to be found in the orchid family ; 
but the recent discoveries made by Pouyanne, Godtery 
and Mrs. Edith Coleman have revealed equally compli- 
cated relationships and have indicated the necessity for 
close scrutiny of the behavior of insects that pollinate 
orchids. 
In February 1916, in the Journal de la Société Na- 
tionale d’ Horticulture de France there appeared the first 
of aseries of articles contributed by Monsieur A. Pouy- 
anne and submitted to the Society by Monsieur Henry 
Correvon. Pouyanne, during his long residence in Algeria 
where he served as President of the tribunal of Sidi- Bel- 
Abbés, had observed the pollination of several species of 
Ophrys and had arrived at truly startling conclusions; 
indeed, he had arrived at conclusions so startling that 
painstaking confirmation, carried on through twenty 
years, preceded their publication. 
Pouyanne observed pollination in Ophrys speculum 
[3] 
