STRUCTUEE AND BIOLOGY OP SCHIZONEURA LANIGERA. 653 
The Structure and Biology of Schizoneura 
lanigera, Hausmann or Woolly Aphis of 
the Apple Tree. 
Part I. — The Apterous Viviparous Female. 
By 
J. Davidson, IVI.Sc. 
(Livei-pool). 
(From the Cooper Laboratory for Economic Research, Watford, Herts.) 
With Plates 38-42, and Text-figs. A-D. 
I. Introduction. 
The wide distribution of Schizoneura lanigera and its 
importance as a serious pest to fruit-growers is generally 
recognised by workers on economic entomology, and so far as 
I am aware, no detailed account of the structure of this insect 
has been given before. It therefore seemed to me very 
desirable that a study of the anatomy of this species should 
be carried out. 
In the present paper I propose to treat of the structure of 
the apterous viviparous female, and hope shortly to complete 
the study of the winged viviparous female and other stages, 
which will be the subject of the second part of this paper. 
I desire to take this opportunity of expressing my sincere 
thanks to Mr. W. F. Cooper, who has most kindly given me 
every facility for cai’rying on this work, and to Mr. L. E. 
Robinson for the generous and kind way in which he has 
given me advice during its progress. 
