244 REPORTS ON INVESTIGATIONS AND PROJECTS. 



(5) J. T. Nichols. The inheritance of skeletal dimensions among guinea-pigs. The 



results of these two related investigations have not yet been fully analyzed, but 

 the inheritance is apparently fully blending. 



(6) A. S. Pearse. The inheritance of polydactylism in guinea-pigs. A continuation of 



the investigation described in Publication No. 49 of the Carnegie Institution of 

 Washington. 



(7) W. G. Vinal. Certain problems in color inheritance among guinea-pigs. In progress. 



(8) H. E. Walter. Ear-length and color-inheritance among rabbits. This first part is 



finished and nearly ready for publication, the second part in progress. 



(9) A. Gulick. Skeletal characters of the sterile hybrids between the guinea-pigs and 



Cavia aperea. 



Dr. Mark reports that a good beginning has been made on the study of 

 the sexual cells of hybrid fowls, and satisfactory methods of fixation and 

 staining have been worked out. As rapidly as the material can be spared 

 from the station at Cold Spring Harbor, where it is being bred for this and 

 other experiments, it is being prepared by Miss Lutz for microscopic study. 



A study of the histological conditions of the male sex-cells in domesticated 

 guinea-pigs {Cavia cobaya) and in hybrids resulting from crosses of these 

 with the wild guinea-pig (C aperea) has also been carried on. Several 

 thousand section.s have been prepared, and it has been possible to make out 

 from these marked differences between the domesticated and the hybrid 

 individuals, which it is hoped may lead to valuable results. 



It has also been possible to reach some interesting results in the study of 

 the formation of spermatozoa in honey bees, and a preliminary paper cover- 

 ing some of the points established has already been published by us. These 

 studies will be extended to embrace other Hymenoptera, material for which 

 has been secured during the past summer, 



Crampton, Henry E», Columbia University, New York, N. Y. Grant No. 137. 



Determination of the laws of variation and inheritance of certain Lepidop- 



tera. (For previous reports see Year Book No. 2, p. xli, Year Book 



No. 3, p. 136, and Year Book No. 4, p. 276.) $500. 



Report. — In continuing the work of former years additional pedigreed 



families of Philosamia cynthia have been reared, and statistics relating to 



elimination, sexual and other forms of selection, correlation, and inheritance 



have been obtained for more than 2,000 additional individuals. Of the four 



series of pupae produced during the previous j^ear (as described in previous 



reports) more than 4,000 became moths in June and July, 1906, and these 



were mated in 425 cases. Three hundred and nine of these pairs gave 44,418 



eggs. Only 69 families, however, were reared, and these gave 2,196 cocoons 



in August. As in previous years, it was found that some individuals emerged 



during the latter part of the summer when they were reared, although there 



were less than 200 such cases this year. The moths that emerged were 



mated in nearly 50 instances and 5,845 eggs were obtained from these pairs. 



Some of these are now being reared. 



