EXPERIMENT STATION REPORT. 603 



that these were males, which were now in the pnpal stage, resting 

 beneath the scales. One large leaf, bearing a number of parasitized 

 scales, was examined with the following result : 



Total number of scales on the leaf 898 



Good scales — apparently females 723 



" " " males — in pupal stage 108 



Parasitized scales — parasites not yet emerged 32 



" " " emerged 35 



Judging from the condition of the males, they were mature and 

 ready for copulation. 



August 30th, other twigs collected at New Brunswick were ex- 

 amined in a jar at the laboratory. A number of parasites and male 

 Pidvinaria was found, and a few of the latter were copulated with the 

 females. As previously observed the insects moved readily when dis- 

 turbed. 



A few days later a box of twigs was received from Plainfield, with 

 the insects in the same condition, while the upper surface of the 

 leaves was quite black and sooty, caused by a fungus growing on the 

 "honey-dew" excreted by the insects. 



In Montclair, also, I found that some of the very few scales on the 

 leaves were males, while the female scales were mostly parasitized, so 

 that with the Coccinellicl larvae eating the larger part of the eggs and 

 young larvffi, the beetles devouring the young sets and the parasites 

 infesting the remainder, the scale has been about cleaned out where 

 it was so abundant in 1904. 



A few infested leaves were collected from trees along South Orange 

 Avenue, in Vailsburg, and on one of them I found 298, while another 

 showed 136 parasitized scales, and many of the leaves showed just as 

 many. Infested leaves gathered in New Brunswick now showed nearly 

 as large a number of parasitized forms. 



September 13th, at Irvington, I observed several maples on which 

 there was considerable infestation, and here, as elsewhere, there were 

 parasitized forms. I also noticed that a few of the insects were start- 

 ing to migrate from the leaves to the twigs. Up to' this time the sets 

 had been, with few exceptions, on the leaves, but now a few were 

 observed on the leaf petioles and on the twigs. However, the general 

 migration took place later, and, as it was gradual, was not completed 

 this year until after the middle of October. Even then a few tardy 

 insects were caught and fell with the leaves. Several examinations 



