180 A Stud If of the Capsid Bags found on Apple Trees 



The problem has been studied mainly from an economic standpoint, 

 our main object being to find out the amount of damage caused by each 

 species, to study their life-histories and tlie nature and cause of the 

 injuries done to the leaves, shoot and fruit by the various stages. 



Problems of great biological interest and possibly of economic impor- 

 tance have arisen during the course of this work which we have been 

 unable to investigate owing to pressure of time. One season is a very 

 short time to study all the aspects of such a problem as this, and we hope 

 if circumstances permit to continue this work next season. Our justifi- 

 cation for the publication of this rather incomplete paper is in the hope 

 that the observations contained in it may be of immediate use in helping 

 to control this serious pest, and also that under such abnormal con- 

 ditions as exist at the present time, the authors may be tinable to 

 continue this work, in which case the observations made may be of 

 some help to future investigators. 



A large number of the Capsidae live on the juices of plants which they 

 suck by means of their long rostra, and it is probably as a consequence of 

 this that so many of them have been recorded, some rightly and others 

 wrongly, as plant pests. In America the following have been recorded as 

 damaging fruit trees : 



Heterocordylus malinus Reut. 

 Lygidea mendax Reut. 

 Lygus jyratensis Fab. 

 Neurocolpus nuhilus Say. 

 Paracalocoris colon Say. 



Fryer points out that of these only Lygus pratensis is present in this 

 country. 



In England the following among others have been recorded as 

 damaging apple trees: 



Atraciotomus mali Mey. 

 Lygus pratensis Fab. 

 Orthotylns marginalis Reut. 

 Plesiocoris rugicollis Fall. 

 P sail us ambiguus Fall. 



Lygus pratensis is recorded as producing dimples on apples, whereas 

 the others are recorded as damaging the leaves, shoots and fruit. 



As Fryer has pointed out (H) there is a great deal of confusion 

 as regards the real pest and the status of the various capsids found so 

 commonly in affected orchards. Unfortunately the presence of a species 



