194 A Study of the Capsld Biujisfoniid on Apple Trees 



.usually flew towards the window in an almost horizontal direction, but 

 some flew upwards and a few reached the ceiling. 



Time and nature of injury. 



In 1917 a very severe and prolonged winter was followed by a 

 warm spring, the former retarding the opening of the buds and also 

 the hatching of P. rugicollis. Fryer records them as hatching before 

 April 14th in 1913 and in 1916 a few newly hatched bugs were found on 

 April 25th. In 1917 the first markings were seen on May 7th, but under 

 warmer conditions in the laboratory a few hatched on May 5th. At this 

 date the buds were opening rapidly, the diameter of well-opened buds 

 being about one inch and a half, with the outer leaves about an inch long. 

 The first attack started immediately after hatching and in a day or two 

 a large number of buds showed the characteristic purple brown markings 

 on their leaves. The number of attacked buds continued to increase 

 rapidly on account of new larvae which kept hatching until May 13th 

 and also because the earlier hatched larvae moved from one bud to 

 another. It is probable that the hatching period. May 6th-May 13th, 

 is shorter than the normal period owing to the warm condition obtaining 

 at this period in 1917. 



In some varieties and notably Lord Derby the leaves remained curled 

 much longer than in other varieties and provided more shelter for the 

 bugs. The time of full bloom of Early Victoria, Lord Grosvenor and Lady 

 Hollendale was on May 23rd, i.e. about seventeen days after the bugs 

 started to hatch and during this time the leaves were the source of food. 

 In some varieties, e.g. Grenadier, the opened leaves were soon used up as 

 a source of food and were very badly damaged, the bugs then began to 

 feed on the closed part of the buds. This variety received a very bad 

 check from the marking of the young leaves which did not expand to any 

 extent (see PI. XI, fig. 14 b). 



When the fruit set the bugs were mostly in the foui'th instar, some 

 third and fifth instars also being present. These bugs began to mark the 

 fruit on May 28th, very soon after setting. All the last three nymph 

 stages and the adults damage the fruit. In cages in the laboratory they 

 did not show any marked preference for the fruit but fed upon leaves and 

 fruit alternately and seemed to be quite satisfied to feed at the place 

 where they were put, except on old leaves. 



They did not attack the fruit after it was over an inch in diameter ' 

 but turned their attention to the young leaves and succulent part of the 

 stem. When the adults appear the fruit is a fair size and not much 



