136 



30 days between the hatching of 5. padi and A. pomi. The period 

 between the hatching of the first and last eggs shows a similar regional 

 variation. 



The most marked regional difference in reference to summer activities 

 was the time of appearance of winged forms. In 1916 in New York 

 the second generation of 5. padi consisted entirely of winged indi- 

 viduals, which quickly disappeared from the apple. During experi- 

 ments with A. sorbi in 1919, the cage was kept constantly moist, 

 thus reducing the temperature, raising the relative humidity, and 

 inducing the tree to continue a rapid and succulent growth. Wingless 

 viviparous females were produced throughout the summer and were 

 present until killed by frosts in late November. There was apparently 

 no tendency to produce oviparous forms in the autumn, and there is 

 no indication that this species could maintain its existence on apple 

 alone for more than one season. A. pomi produced about 90 per 

 cent, of winged forms in the second generation ; this is apparently 

 characteristic of this species under the Eastern climatic conditions, 

 as is also the scarcity of winged forms of later generations. In Western 

 Oregon winged forms are not generally numerous in the second genera- 

 tion, the migratory forms occurring in larger numbers in the later 

 generations than is the case in the East. The hibernation of A. pomi 

 in Oregon is similar to that occurring elsewhere. 5. padi passes 

 the winter chiefly as viviparous females on grains and grasses, where 

 growth and reproduction occur during the winter months, when the 

 temperature is favourable. A. sorbi continues reproducing throughout 

 the winter on plantain ; a few migrants are produced, which return 

 to apple in the autumn. During the winter of 1919-20, this species 

 withstood a temperature of — \3° F. on plantains in the field protected 

 by snow. These low temperatures are not withstood without pro- 

 tection. Winged forms occur in the spring and spread the infestation. 



These regional variations in the behaviour of apple Aphids are of 

 great significance to commercial fruit-growers, and must be taken 

 into consideration when organising remedial measures. A. sorbi must 

 be combated on plantain as well as apple if it is to be eradicated in 

 Western Oregon. The failure of the delayed dormant spray of nicotine 

 sulphate to control this species in Western Oregon is probably due to 

 the long drawn out hatching period more than to any other factor. 



QuAYLE (H. J.). Life History of the Codling Moth in Walnuts at 

 Santa Ana, California.—//. Ecoji. Ent., Geneva, N.Y., xiv, no. 5, 

 October 1921, pp. 440-444. [Received 13th January 1922.] 



The larvae of the codUng moth [Cydia pomonella] hibernate in 

 cocoons under the loose bark of walnut trees, in old cuts, under bands 

 or in any such protected places. Pupation lasts from 18 to 30 days, 

 and occurs from the beginning of April to the 19th June on walnuts, 

 and about ten days earlier on apple. The moths emerged from walnut 

 from the 24th April to the 30th June, and the first eggs were observed 

 on the 8th May on pears, on the 12th May on apples, and on the 

 14th May on walnuts. Oviposition continues until early in July. 

 The larvae hatch in from 10 to 20 days. The maximum emergence of 

 larvae occurs during the second week in June on walnuts. These larvae 

 try to enter at the calyx of the nut, but as the nuts harden, they enter 

 at other points, especially where two nuts are in contact. An average 

 of 35 days are spent in the nut, but some larvae were still found in them 

 after 69 days. 



