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AN INTRODUCTION TO ENTOMOLOGY 



The pine-leaf scale, Chionaspis piniJdlicB. — This is a very common 

 pest of pine, spruce, and other coniferous trees, throughout the 

 United States and Canada. It infests the leaves of its various hosts. 

 The scale of the female is snowy white in color, with the exuviae 

 light yellow ; it is usually long and narrow, as represented in Figure 

 534, 2b; but on the broader-leaved pines it is often of the form shown 



Fig. 537. — Aulacaspis rosce: i, scales on rose, natural size; la, scale of female, 

 enlarged; ib, scale of male, enlarged. 



at 2C in the figure; this is the typical form of the scale of the female 

 in the genus Chionaspis. 



The rose-scale, Aulacaspis ros<s. — This species infests the stems 

 of roses, blackberry, raspberry, dewberry, and some other plants. 

 The infested stems often become densely coated with the scales. 

 The scale of the female is circular, snowy white, with the exuvias light 

 yellow and upon one side (Fig. 53 7, la). The scale of the male is also 

 white; it is long, tricarinated, and with the exuviee at one end (Fig. 

 537, ih); it measures 1.25 mm. in length. 



The San Jose scale, Comstockdspis perniciosa. — The San Jose scale 

 was first described by the writer in 1881, under the name Aspidiotus 

 perniciosus. It has since been made the type of a new genus, Com- 

 stockaspis, by MacGillivray ('21). At the time it was described it 

 was known only in Santa Clara County, California. But in describing 



