Proceedings, ]I)23 Ifi") 



creek banks, mueli of wliifli was coated witli scale, nioi-e esijeeially the 

 Red Osier Dogwood. In tlie Spring- of 1920, these trees were earefull.v 

 gone over for the purpose of ascertaining whether the mite had become 

 established, cuttings being taken and the scale examined under tiie bin- 

 ocular. These investigations revealed the fact that the Hemisarcoptss 

 was numerous, and that many eggs had been destroyed. At the same 

 time the native vegetation was gone over to some extent and the mite 

 discovci-ed some 200 yards distant from the point of liberation in 1917. 



In the Spring of 1921, a more extended search was undertaken, and 

 as a result the mites have been found to be quite numerous at a distance 

 of one and a-half miles from the originall.v infected trees. In this district 

 the mite was, as far as obsevations have been carried out, almost entirely 

 confined to tlie native vegetation along the creek banks ; this maj- be due 

 to the fact that the ti-ees infected in 1917 were isolated by at least one- 

 half mile of open country on one side before the nearest apple trees were 

 encountered, and upon the other by a belt of willows, and various 

 indigenous trees which follow the course of the creek. All the cultivated 

 orchai'ds lay be.vond the creek on that side. 



The accompanying chart shows the distribution of the Hemisarcoptes 

 in this locality, and gives some idea of the condition already referred to. 

 In order to carry the infection to districts somewhat distant from .the 

 l)oints of recovery, in 1921, scale-infested twigs wim-c taken in the south 

 Vernon area from trees known to harbour mites, and were placed upon 

 trees at the Coldstream; apple and dogwood were used in all these cases 

 for the introduction of the mite. In all, nineteen separate infections were 

 made during the spring and summer of 1920-21, the same procedure 

 being followed as in the original transference carried out in 1917. 



The IlABiTh; .\n'd Appe.vk.^nce of Hemisarcoptes maeus 

 In order that the I'ehition of the Hemisarcoptes to the Oyster shell 

 scale may be clearly comprehended, a brief summary of the life history 

 of the latter insect is advisable. Much of the following account is taken 

 from the paper of Dr. J. D. Tothill, already referred to. 



In the Okanasian the eggs of the scale hatch approximately during 

 the entl of ilay, or early iu June, dependent upon climatic conditions. 

 The newly hatched nymphs, after wandering around for a few hours, 

 settle down and insert their mouth jiarts in the bai'k, in which jiosition 

 tlie insect remains fixed foi- the remainder of its existence; the scaly 

 covering, wdiich consists of the moulted skins of the individual being 

 gradually enlarged until maturity is reached, wliich, in the Okanagan 

 Valley, will be some time in late July, or early August, and at that time 

 the eggs of the scale insect will be found to have made their appearance. 

 These eggs remain beneath the parent scale until the following ^May or 

 June, a period of ten or eleven months, and during practically the whole 

 of that period the predatory mites have undisturbed access to them. 



