Dec, 1910.] Proceedings of the Society. 271 



Station, in working with poultry had obtained negative results in selecting 

 eggs to obtain modifications in the chickens. 



Dr. Lutz, himself, had been continuing his work with the fruit fly, Droso- 

 phila ampelophila, and by selection for decrease and increase in the number 

 of veins had obtained results evidently not produced before in nature. He 

 had worked with some 200,000 f^ies, one lot of which came from Huntington, 

 L. I., and another from Boston and Pennsylvania. By careful selection he 

 had obtained 100 per cent, abnormality in extra-veined specimens which he 

 was able to continue for several generations. In like manner he was able to 

 obtain flies with the tips of the wing veins lacking, but these possessed wings 

 so weak that they drooped on the banana upon which the flies were fed and 

 so were killed off and the strain could not be continued. He had been able to 

 breed from a normal to an abnormal strain in eight generations and con- 

 cluded that artificial selection had had a decided effect upon the insects. In 

 considering the question of the abnormal strain reverting, he liberated in a 

 battery jar, in one experiment, the most abnormal specimens of the abnormal 

 strain and in twelve generations, covering a period of twenty-four weeks, they 

 went back to the normal form. In a second experiment, he released in a 

 battery jar an equal number of normal and abnormal forms and in three or 

 four generations the flies reverted to the normal form. He believed the active 

 force at work in these experiments was sexual selection. 



Dr. Lutz then reviewed some of the facts discussed by Tower in his 

 paper on " F.volution in the Chrysomelid Beetles in the Genus Leptinotarsa." 

 Tower has pointed out that Leptinotarsa decemlineata has been derived from 

 intermedia which has its habitat in central Mexico. The latter form spread 

 northward along the routes of travel, where the form decemlineata became 

 prominent and it in turn spread first northward along the buffalo trails and 

 later through the introduction of the potato, eastward to the Atlantic sea- 

 board. The form juncta retreated before the form decemlineata. In moisture 

 and temperature experiments he found that the deviation from the normal 

 produced first melanism and, as the deviation increased, albinism. By varying 

 conditions of humidity and temperature and exposing females to these changed 

 conditions for a period just preceding oviposition, forms were obtained which 

 held their variation through several generations, even when allowed to breed 

 under natural conditions. By abnormal environment, also, a strain having 

 five annual generations has been obtained while three is the greatest number 

 that naturally occurs in this group. 



Mr. Leng spoke of the color variations that occurred in some of the 

 Coccinellidae, and asked whether Dr. Tower had obtained any structural differ- 

 ences. Dr. Lutz said he believed that he had. 



Mr. Davis called the members' attention to Bull. No. ^^ of the Louisiana 

 Crop Pest Commission, by W. Newell, dealing with the treatment of the boll 

 weevil by the use of powdered arsenate of lead, and also the comment upon 

 it by Mr. Hunter in Science. Mr. Davis suggested that the success of this 

 method would do away with the necessity of destroying the scenic effects 

 necessitated by destroying the hibernating places of the insects. 



