340 



yielded 21 generations between 1st May and 10th December in 191*1. 

 The age at which reproduction began varied from 7 to 26 days ; the 

 length of the reproductive period varied from 4 to 36 days and the 

 death of the female usually occurred on the day following the cessation 

 of reproduction. The average duration of life of viviparous females 

 was 31*7 days and of hibernating females 134 days. The maximum 

 number of young produced by any female was 142, reproduction being 

 most rapid in July, August and the beginning of September. Wingless 

 viviparous females mature more rapidly and have greater powers of 

 reproduction than winged forms. 



Smulyan (M. T.). Observations on the Life-Histories and Habits of the 

 Species of Aphides most common on the Cultivated Apple {Malus 

 mains) in Virginia (Blacksburg), during the Season of 1915.^ — lOtk 

 Rept. State Entomologist and Plant Pathologist, Virginia, 1914-1915^ 

 Richmond, 1916, pp. 64-75. [Received 6th June 1916.] 



Apple trees in Virginia are attacked by Aphis sorbi, Kalt. (rosy apple 

 aphis), A. avenae, F. (oat aphis), and A. pomi, de G. (green apple aphis). 

 The last-named species remains on the apple throughout the year, 

 while A. sorbi migrates to plantains and A. avenae to cultivated and 

 wild grain and grasses. A. avenae was the first species to appear in 

 spring, being found on 25th March on mature trees before the buds 

 were open. These individuals died from lack of food, and actual feed- 

 ing was noted on 8th April when the buds were opening. No definite 

 relation was observed between the time of hatching and the unfolding 

 of the buds. Stem-mothers were reproducing by 21st April and nine 

 days later winged forms appeared. This species probably causes, 

 injury by feeding on the blossoms which, as a result, drop early. 

 Coccinelhd larvae were abundant by the second week in May and 

 destroyed numbers of Aphids. Migration on the part of the latter 

 was completed by 31st May. Winged, viviparous, return migrants 

 were found on apple on 2nd October when they were depositing sexual 

 young. The latter reached maturity by the middle of October, when 

 egg-laying began and continued until December. Viviparous forms 

 began to decrease in numbers during the third week in November. 

 In some cases males of A. sorbi were observed pairing with females of 

 A. avenae. Eggs were deposited in protected places in the bark or 

 around the buds of twigs one or more years old of mature trees. 



A. sorbi is almost confined to bearing trees. The first young were 

 observed on 7th April and a number of terminal buds began to open 

 on the next day, although many were still closed. There is thus no 

 definite relation between the time of hatching and the time of the 

 unfolding of the buds. Hatching was completed by 20th April. 

 Curling of the leaves was first observed on 22nd April, and on 24th 

 young of the second generation were found. Mature females of the 

 second generation were present on 5th May. Colonies were most 

 numerous in thick trees in positions in which the young forms were 

 protected from the sun ; a few individuals of A. avenae were usually 

 present. Spring migrants were first observed on 18th May, about a 

 week after most of the petals had fallen. A few individuals were 

 present on the tender foliage throughout July after the majority had 

 migrated to plantains. Some migration was observed as late as the 



