THE 
Vor. XXIX. February, 1895. 338 
THE PHILOSOPHY OF FLOWER SEASONS, AND 
THE PHAENOLOGICAL RELATIONS OF 
THE ENTOMOPHILOUS FLORA 
AND THE ANTHOPHILOUS 
INSECT FAUNA. 
By CHARLES ROBERTSON. 
The writer’s determination to discuss the subject of flower 
seasons at the present time is owing to the publication, by Mr. 
Henry L. Clarke, of an interesting and suggestive paper on 
the same topic in the Narura.ist for September, 1893. Hav- 
ing been engaged since 1886 in the investigation of the mutual 
relations of flowers and insects, he has been led in a very nat- 
ural way to consider the time of blooming of flowers adapted 
to insects and the time of flight of the insects which depend 
more or less upon a floral diet. In 1890 a tabulation of both 
groups was begun, based upon the data then at hand, and 
since that time the author has had lying before him lines 
indicating the periods of the separate species and curves indi- 
cating the periods of the families of entomophilous plants and 
of the genera of bees, and the families of the principal remain- 
ing anthophilous insects; all, however, in the process of being 
modified by the accumulation of data. As a result, certain 
views have been arrived at regarding the relations of the 
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