514 RECORDS 



forms, together with 54 other genera and a great many species 

 (100 to 150) were found in the waters of Van Cortlandt Park 

 during the past fall. 



The second paper was designed to be the first of a series 

 dealing with the problems of variation and selection inLepidoptera, 

 and especially in the Saturnid moths. The particular questions 

 here considered are as to the relative variability of eliminated and 

 surv^iving pupae and moths oi PJiilosamia cynthia, and as to the 

 relative variability of males and females. From a lot of 1,090 

 cocoons from a restricted locality, 3 ro living and 632 dead pupa^ 

 were obtained, the remainder being shrivelled or abnormal 

 larvae and pupae. The living pupae were compared with an 

 equal number of dead pupae with reference to certain body-char- 

 acters (length, length of bust, width, depth, frontal stature and 

 sagittal stature of bust), and to certain characters of a typical 

 organ, the left antenna (length, breadth and stature). It ap- 

 pears that the surviving males are slightly less variable than the 

 eliminated males, and that the surviving females are far less 

 variable. From the living pupae but 180 perfect moths were 

 obtained. The males were from pupae which were far less 

 variable than pupae producing abnormal moths ; but the females 

 were from relatively more variable pupae, though the latter were 

 much less variable than eliminated female pupae of the preced- 

 ing group. The paper will be published in full. 



Professor Wilson presented the results of a study of the 

 phenomena of development in the unfertilized eggs of Texepneu- 

 stcs when treated with solutions of magnesium chloride by 

 Loeb's method. The results confirm Loeb's conclusion that the 

 embryos arising from these eggs are produced without fertiliza- 

 tion by spermatozoa, conclusive proof being given in the fact 

 that during cleavage the number of chromosomes is half the 

 usual number, namely, 18 instead of 36. The mitotic phe- 

 nomena differ in many details from those occurring in fertilized 

 eggs, but show a striking general parallelism to them. The asters 

 may be only two in number (cleavage asters), but as a rule 

 there are many other asters (cytasters) that have no connection 

 with the nucleus. Like the nuclear asters, however, the cytas- 



