10 



always, has a tiny depressed ring or groove around it. This circular area is easily 

 seen with a hand lens, and is commonly yellowish in color, though sometimes black, 

 (c) The Black or Winter iStaye. (bee i^'ig. 3 A bb) : — At tiliis stage the scale 

 is very small, looking to the naked eye like a tiny black speck, A hand lens is 

 absolutely necessary to make out any of the details. An examination of fig. 3A b 

 shows that it is circular, flattened, not more than 1-10 the size of an adult female, 

 and about half the size of the male. It has a little nipple in the centre surrounded 

 by a depressed ring or groove. The nipple and depressed ring around it, along 

 with the black color, are the most important characteristics to remember. Some- 

 times the color varies a little and the nipple may be whitish, frequently the outer 

 margin of the ring is whitish, but usually in Ontario every part of this stage is 

 black. As said above, this is practically the only stage in which the insects pass 

 the winter. Of course adult females and very young scales are to be found in early 

 winter, but they apparently all die. 



Other Scale Insects Allied to and so -Closely Resembling San Jose 

 THAT THEY ARE Often MISTAKEN FOR IT. — Such scalcs as the Oyster Shell, Scurfy 

 and European Fruit Lecanium, or, as it used to be called. New York Plum Scale, 

 are so much larger, especially the last named, and so different in shape that no one 

 who has read the above account and examined the figures could for a moment mis- 

 take any of them for San Jose. There are, however, in Ontario probably a dozen 

 scales belonging to the same genus (Aspidiotus) as the San Jose, but only four of 

 these are at all commonly found. These are: 1st, the European Fruit Scale, or, as 

 many of us are accustomed to call it, the Curtis Scale {Aspidiotus osireaeformis) ; 

 2nd, the English "Walnut Scale (Aspidiotus juglans-regiae) ; 3rd, the Putnam Scale 

 (Aspidiotus ancylus) , emd 4:ih, the CheTTj Scale (Aspidiotus forhesi) . None of these 

 scales are very destructive in Ontario orchards. The first of these, the European 

 Fruit Scale or Curtis Scale, is common on apple trees, especially on the very 

 large branches where it may often be found under the loose bark, though it by no 

 means always feeds under shelter. It is the only one of these four that I know of 

 that is ever found on the fruit. During the last two years I have seen several 

 apples with these scales on them, and resembling so closely the San Jose scale that 

 they would usually be mistaken for it. The resemblance is increased by this scale 

 having the same power as the San Jose to cause a reddish discoloration of the fruit. 

 The English Walnut Scale has not, I think, been found on fruit trees in Ontario, 

 though in other places it does attack them. In St. Catharines it is very abundant 

 on soft or white maple (Acer saccliarinum) . I have also had it sent in on poplar, 

 and Prof. Jarvis has found it on willow. I find both it and the previous scale 

 heavily parasitized. The Putnam and Cherry Scales are not very common, though 

 they are occasionally sent in. They attack the bark of orchard trees and of a few 

 other trees. I have never seen one on the fruit itself. 



I had planned to add a key for the identification of these four species, but they 

 vary so much with the different kinds of bark on which they are found, and at 

 different times in the season, that no matter how carefully and accurately the key 

 might be made there would always be the danger of mistakes ; hence when in doubt 

 the best way will be to send specimens for identification to the Department of 

 Entomology, O.A.C., Guelph, or to the Dominion Entomologist, Central Experi- 

 mental Farm, Ottawa. Many of the best students of scales find it necessary at 

 times to clear the insect itself beneath the scale in certain solutions and then 

 examine what is known as its anal plate under a compound microscope. A study 

 of this part is the final test of its identity. 



