104 REPORTS ON INVESTIGATIONS AND PROJECTS. 



that the hybrids between these two species might be successfully 

 reared to maturity, so that the behavior of the maternal and paternal 

 chromosomes during sex-cell formation could be studied. About 

 4,000 hybrids (Fundulus heteroclitus X F. diaphanns) were hatched. 

 On August 16, 1904, about 1,500 of these were successfully trans- 

 ported in Mason jars to Bloomington, Indiana. These were kept 

 alive until September 20, 1904, when the last died. It was found 

 impossible, under the adverse water conditions at my disposal, to 

 keep down the attack of fungus. 



A careful study of the germ glands of the three species of Fundulus 

 has convinced me that fishes are unfavorable forms for the study of 

 chromosomes in sex cells. This fact also determined me not to 

 attempt the cross between the whitefish and lake herring which I 

 had planned. 



A portion of my time during the summer of 1905 was devoted to 

 the problem of the variability of the sex ratios and their modification 

 through selective breeding. The forms experimented upon are 

 three species of flies. The experiments are not far enough along to 

 permit of a statement of the results. I have at present (October 15, 

 1905) the data on 14 families. From these I isolated 2,378 eggs. 

 The number of eggs hatched, the number that emerged, and the sex 

 ratios of each of the families were determined. This is an exceed- 

 ingly laborious process, but my experience during the past winter 

 has shown that in selective breeding for one sex or the other it is 

 essential that account be taken of the mortality during the life history. 



CLIMATIC DATA. 



The first frost of 1904-05 occurred October 16, 1904. The first 

 killing frost was on the 27th of the same month. The last freezing 

 temperature was on May 2, 1905. The last frost was May 2, with 

 a close approach to frost (37 ) on May 21. The first frost in the 

 autumn of 1905 was on October 8 ; the first killing frost October 31. 

 The first snow fell November 25, 1904. The ground was covered 

 with snow December 8 to January 19, and January 25 to February 28. 

 The last snow flurry was on April 17. 



