BIOLOGY, EXPERIMENTAL — DAVENPORT. I05 



REPORT OF DR. E. N. TRANSEAU. 



Since coming to the Station in July most of my time has been spent 

 in the study of the local plant societies. Especial attention has been 

 given to those species which occur in more than one habitat, as they will 

 probably furnish the material for future experimentation. Herbarium 

 and alcoholic specimens of these plants have been collected for a further 

 study of their structural variations. It is hoped that this work will point 

 the way to field experiments on habitat modifications and selection. 



On the other hand, several species are being cultivated in order to 

 determine the range of their variability in a single habitat. When the 

 habitat experiments are begun, it is hoped that they may be conducted 

 with pedigreed seeds of plants whose variation in a single habitat is 

 known. 



In order to differentiate the effects of the various soil and meteorolog- 

 ical factors, measurements by means of recording instruments should 

 be made throughout the growing season. When the habitat character- 

 istics and their united effects on plants are known, control experiments 

 in the plant-house will aid in the separation of the individual factors. 



REPORT OF DR. W. J. MOENKHAUS. 



During the past two years my work has been principally on the sex 

 ratio in Drosophila, with especial reference to its control by selection. 

 Data on over 10,000 individuals have been obtained ; most of this is pedi- 

 greed. I consider the results sufficiently definite to warrant publication 

 and they are about ready for the press. 



REPORT OF DR. N. M. STEVENS. 



My work at Cold Spring Harbor was a study of the germ-cells of 

 Coleoptera, with reference to the problem of sex determination; also 

 some observations on aphids with reference to correlation of color with 

 sex. I also began studying the banana-fly in connection with the same 

 problem — sex determination. 



Miss Boring, who was with me for six weeks, was makmg a compara- 

 tive study of the germ-cells of several families of the Hemiptera-Homop- 

 tera, especially the Membracidas, Fulgoridse, and Jassidse. 



