4 EXPERIMENTAL POLLINATION. 



concerned species that are probably outside the normal experience of the 

 visitors. Some studies have also been made in the plains grassland at 

 the base of the range, and in the alpine meadows on the summit of Pike's 

 Peak, as well as a few preliminary ones in Arizona and California, but these 

 are reserved for the most part for a later treatment. 



For the flowers the nomenclature is that employed in Clements and 

 Clements' "Rocky Mountain Flowers," while the names of the Lepidoptera 

 are those found in Holland's "Butterfly Book" and "Moth Book." In the 

 other groups the determinations have been made by the following specialists, 

 to whom grateful acknowledgment is made: Dr. J. M. Aldrich, Bureau of 

 Entomology, Washington, D. C; Professor T. D. A. Cockerell, University 

 of Colorado, Boulder, Colorado; Professor C. Howard Curran, University 

 of Kansas, Lawrence, Kansas; Dr. F. E. Lutz, American Museum of Natural 

 History, New York; Professor S. A. Rohwer, U. S. National Museum, 

 Washington, D. C; Professor 0. W. Oestlund, University of Minnesota, 

 Minneapolis, Minnesota; Professor M. W. Swenk, University of Nebraska, 

 Lincoln, Nebraska; Professor C. T. Vorhies, University of Arizona, Tucson, 

 Arizona; Professor H. L. Viereck, Biological Survey, Washington, D. C. 



Objectives. — As already indicated, the primary object of the present 

 investigation is to place the study of the flower in relation to its environ- 

 ment on the basis of experiment and measurement. At the same time it 

 is intended to give the fullest value to the synthetic nature of the problem 

 by placing the chief emphasis upon the mutual relations of flowers and 

 insects. The life-history of the flower has been given greater attention 

 than heretofore and it is felt that the life-history of the insect in the broader 

 ecological sense must receive similar study. The central theme is attraction 

 and the behavior of the insect at the flower, and in spite of the work already 

 done, this offers an enormous opportunity for quantitative research. The 

 efficiency of both flower and insect is susceptible of much greater accuracy 

 of measurement and it appears probable that this will disclose a new field 

 of correlations. In this connection the experimental study of competition 

 is especially significant and promises to throw a flood of light upon reciprocal 

 adaptation, as is likewise true of mutilation experiments. This leads to 

 the consideration of the evolution and phylogeny of flowering plants under 

 the influence of insect and wind pollination, as well as a re-examination 

 of the effectiveness of cross and self pollination. With respect to the 

 insects the major queries concern the respective roles of the senses, the 

 acquisition and fixity of habits, and the relation between instinct and 

 intelligence. 



METHODS. 



General principles.— An endeavor has been made to develop a compre- 

 hensive system of research, based primarily upon experiment and measure- 

 ment. This has been made as complete as possible, though it is fully 

 recognized that the further development of this great field will reveal new 

 objectives and new methods of attack. The great majority of the methods 

 have been tested in the present study, others are now being used in the work 

 under way, and a few are still to be applied. Most of the latter have been 

 employed by other investigators and hence are considered for the sake of 



