December, '15] 



SCIENTIFIC NOTES 



553 



The aphids slowly retreated do"WTiward to the cotton plug in the neck of the bottle 

 where those which did not transform into winged aphids died, presumably from 

 starvation. Under orchard conditions, such aphids should, in the light of the series 

 of tests reported in Phytopathology, scatter bUght to other shoots. It has since been 

 observed in nature by Jones^ who watched a colony of A. pomi vacate a blighting 

 shoot, each individual descending to the base and going up fresh twigs. In thus 

 scattering, they carried infection to seven surrounding clean shoots which blighted 

 within a few days following then attacks. This may help explain the continued 

 activity of blight in many trees where thorough pruning has been resorted to, and 

 supports the view that aphids are among the chief carriers. 



Third, intensive study of fertile stem mothers and later fall-bearing females shows 

 that some mothers drop aU their young in a very circumscribed area, on a given 

 leaf or shoot, while others wander considerably before they are aU through bearing 

 young. Neither method of grouping young can be called unique for any particular 

 species. Furthermore, injury to a young twig such as when blight attacks it, would 

 produce some migration as shown by the above experiments. Under such conditions 

 is it very important to consider the aphids as particularly sedentary? 



Further observations on the habits of these aphids and other common Homoptera 

 ought to be made before we ma}' decide definitely which type of insect is most serious 

 in the distribution of the germs of fire bhght, after bees have stopped working in 

 the blossoms. 



A. C. BURRILL, 



Department of Economic Entomology, University of Wisconsin. 



English Sparrows and Spread of San Jose Scale.^ The English sparrow has 

 been considered, with other wild bu'ds, as carrier of the pernicious scale, but I am 

 not aware that any very thorough study of the relative value of different birds as 

 carriers has been made. 



The following note compiled from a survey for the extermination of scale in Wingra 

 Park, an isolated suburb of Madison, Wis., is a statistical attempt to produce further 

 proof against the sparrow. The district surveyed was bounded on the south by a 

 lake, on the east by a vacant marsh, on the north by a raihoad cut and open lots, 

 and on the west by farm fields, so that we may safely say that there was no possi- 

 bility for the presence of scale within two or three city blocks of the surveyed infested 

 area. In this circumscribed area we may suppose the EngHsh sparrow to be the 

 only imdomesticated bird species which would normally restrict its flight to so smaU 

 an area, and serve as local carrier for short distances, since comparative psychol- 

 ogists consider the English sparrow very local in its habits of flight. 



The area contained sixty-four infested city lots. In these lots aU infested woody 

 plants were either within one hundred feet of each other, or within one hundred 

 feet of some place where Enghsh sparrows regularly came to feed. Places 

 counted as Enghsh sparrow feeding centers were barns occupied by horses where 

 grain feed was regularly exposed in manure piles, and chicken coops, where garbage 

 and grain were regularly exposed. 



The apparent relation between these feeding places and nearby woody plants 

 is revealed by a study of the bird's habits. It is the habit of these birds, when com- 

 ing towards feeding places, to fly into the branches of a woody plant to see that the 



iJones, B. J. The natural modes of distribution of fire blight. Mo, Bui. State 

 Com. Hort. Cal., 3, 12:505-11, 1914. 



2 Published with the permission of Prof. J. G, Sanders, Department of Economic 

 Entomology, University of Wisconsin. 



