68 REPORTS Olf INVESTIGATIONS AND PROJECTS. 



The behavior in this experiment, while differing in its result from that 

 shown by similar cultures in Mexico, is the same in its general effect and 

 shows clearly that two or more species may meet, interbreed, and produce 

 through the combination a new species, or strain. The form C at Tucson is 

 different from the pure deccuilineata growing beside it under identical con- 

 ditions. A, B, D, and E will have been eliminated from the cutlure at 

 Tucson by the end of 1910, judging by the results of similar cultures made in 

 Mexico. 



Cultures of this kind are common in nature, allied migrating races meeting, 

 and interbreeding with resulting combinations or extinction. In addition to 

 the actual interbreeding effects there is the direct action of the physical and 

 biological environment upon the process, and its products. Extended atten- 

 tion to this matter shows that the action of the biological environment has 

 been enormously overestimated. Tests are being made of the action and 

 importance of the physical environment in such cultures, preceding an attack 

 upon the problems of internal relationships and processes. 



In accordance with an agreement approved by the President Dr. Mac- 

 Dougal has accepted the title of honorary lecturer on heredity and evolution 

 in the University of Arizona, and gave a course of four public lectures during 

 the collegiate year of 1908-09. He has also given various addresses and 

 lectures before associations and scientific societies and at the University of 

 California, the University of Chicago, University of Missouri, Princeton 

 University, Columbia University, Delaware Agricultural College, Stanford 

 University, De Pauw University, Washburn College, Vassar Institute, and 

 Brooklyn Institute of Arts and Sciences. 



The Department is frequently requested to furnish living material of 

 desert plants. Compliance with many of these requests would entail field 

 trips of 15 to 30 miles and expenditures for transportation beyond the 

 capacity of the Department. Such requests must therefore be largely turned 

 over to commercial companies. The demand for photographic prints has also 

 become so great as to make necessary that applicants be required to refund 

 expenses of printing. 



EQUIPMENT. 



The Acclimatization Laboratory and grounds at Carmel, California, de- 

 scribed on pages 58, 59 of this report, constitutes the most important acces- 

 sion to the facilities of the Department made during the year. 



Some permanent improvements being necessary in the alluvial experimental 

 tract near the Desert Laboratory, an area of 2.5 acres was purchased and a 

 ruined adobe dwelling was restored, a concrete floor laid, and a roof of oiled 

 dirt put on, to fit this structure for use as a special laboratory in connection 

 with Professor Tower's work with the chrysomelid beetles and other accli- 

 matization researches. 



The development of the investigation of the reactions of the Leptinotarsse 

 and their food-plants to environmental stimuli has necessitated the construc- 

 tion of 30 additional vivaria in addition to a large working shelter, while the 



