330 ANNUAL KECORD OF SCIENCE AND INDUSTRY. 



to be males, while the last lot, consisting of a dozen cocoons, 

 Avere, with only two exceptions, females. 



This suggested to him further experiments in the same di- 

 rection, as the result of which he came to the conclusion, 

 first, that males are the invariable result when the larvae are 

 fed upon diseased or innutritions food ; second, that in the 

 fall of the year, when the leaves have become deprived of 

 their usual amount of sap, males are generally produced ; 

 third, that more males are produced late in the season than 

 females ; fourth, that the sexes in early life can not be distin- 

 guished ; or, in other words, that there would appear to be no 

 such distinction as male and female, the change being brought 

 about late in life through the medium of nutrition. 



These facts are in corroboration of a simple law announcecl 

 by Mr. Thomas Meehan in regard to the vegetable kingdom 

 namely, that sex in plants is the result of grades of vitality, 

 or, as suggested, viability ; and that this power of life is a 

 mere matter of nutrition, the highest grades of vitality, only, 

 producing the female sex. 



In the same number of the proceedings of the Academy 

 Mr. Meehan furnishes an additional illustration of this fact as 

 the result of experiments upon the common black walnut 

 {Jiigla7is nigra), which satisfied him that there is not so great 

 an expenditure of vital force in the production of male as of 

 female flowers. 2 B, 1873, 283-290. 



DISTEIBUTION OF CALIFORNIA MOTHS. 



In an article upon the distribution of the California Moths, 

 communicated by Dr. A. S. Packard to the Boston Society of 

 Natural History, and published in the AmericaJi Naturalist, 

 some interesting conclusions are derived from a study of the 

 subject, which strongly corroborate the views of Professor 

 Gray, in regard to the distribution of plants, as presented by 

 him in his address before the recent meeting of the American 

 Association at Dubuque. The Phalmnidm of California, ac- 

 cording to Dr. Packard, appear to be composed of four ele- 

 ments: first, of species of genera exclusively American (North 

 and South) ; second, species of genera which occur in Europe, 

 especially in Southern Europe around the Mediterranean Sea, 

 Western Asia, and Asia Minor, and even on the Pacific in 

 South America. This is the most characteristic of the fauna, 



