ABSTRACTS. 29I 



in order, the root cycle, the leaf cycle, the tassel cycle and the 

 ear cycle. The reasons for the postulation of these cycles is 

 given in the text. 



8. The observed difference in the manner of growth of in- 

 dividual plants and of groups of plants cannot be explained as 

 the effect of external, environmental factors. 



9. These differences are rather to be looked upon as the 

 eft"ect of internal factors. 



10. The distribution of the average relative size (mean quin- 

 tile position) of individual plants is such as to suggest the 

 random distribution of these factors among the plants. The 

 same thing is brought out by the distribution of the relative 

 measurements of plants starting or ending with a given relative 

 size (quintile). 



11. The simplest method of explaining these facts is to re- 

 gard the dift"erences in the manner of growth as due to inde- 

 pendent Mendelian factors which are distributed at random in 

 any population of open fertilized maize plants. These factors 

 would occur in the proportions found in a stable Mendelian 

 population mating at random. 



12. By assuming the presence of two independent growth 

 factors and weighting each with the proper value, it is possible 

 to obtain a theoretical distribution agreeing very closely with 

 the observed distribution. It is possible that by using more 

 factors even a better fit might be obtained. 



13. The interpretation of the growth of these plants by 

 Mendelian factors is strongly supported by the distribution of 

 the standard deviations of the plants with different relative sizes. 

 Thus it has been shown that the extreme plants which would be 

 more nearly homozygous and for this reason less variable are, 

 as a matter of fact, some fifty per cent, less variable than the 

 plants in the middk class after all allowance has been made 

 for the difference in the size of the means. 



The Immature Stages oe the Tenthredinoidea.* 



This study of the immature stages of sawflies was undertaken 

 in the hope that some information might be obtained as to the 



*This is an abstract of a paper by Alex. D. iMacGillivray with the same 

 title published in the Forty-Fourth Annual Report of the Entomological 

 Society of Ontario, 1913 (1914), pp. 54-75. Plate I with 27 figures. 



