﻿POMONA JOURNAL OF ENTOMOLOGY 



Figure 8. Aspidiotus hederae on lemon 



of the trace, probably due to thrusts 

 of the beak. The evidence seems to 

 show that after the scale has sapped 

 a portion of the leaf, it is able to puil 

 out its rostrum and thrust it into the 

 adjacent cells, and thus move slowly 

 along. This is necessarily a slow 

 process, as is shown by the fact that 

 the longest traces are less than an 

 inch in length, and that these traces 

 represent months of the life of the 

 scale. 



There is no other supposition ten- 

 able, for it is certain that the rostrum 

 of a scale cannot be so manipulated 

 as to penetrate such distances. Many 

 of the traces cross the midrib ,and ex- 

 tend for some distance on both sides, 

 — others are half circles, — all going 

 to show that the scale must have act- 

 ually moved, leaving the yellow trace 

 of withered tissue behind her. A sim- 

 ilar though not so well defined a move- 

 ment, is observable in the red scale. 



Saissetia oleae 



BLACK SCALE. 



At this season of the year we find on the citrus trees only young black 

 scale. The last eggs were hatched out before November and only the hollow 

 shell of the mothers remain. But on the roots of night-shade, (Solanum 

 douglasii ) we find a different state of affairs. Figfure 9 shows all stages of the 

 female scale. This may furnish a ready and constant supply of scale in all 

 orchards not free from this plant. Fumigation will not kill the scale because 

 of their position beneath the surface of the soil, and in no case have I found a 

 scale in the ground parasitized by the Scutellista. They apparently do not 

 attack these root forms, so that control of the Black Scale by this insect is 

 impossible so long as night-shade is allowed to grow under the orange and 

 lemon trees. The farmers have evidently failed to realize the importance of 

 this fact, for night-shade is plentiful in and about every orchard. Even in the 

 best-kept orchards the plants are not uprooted, but cut off near the surface. 

 In such cases new sprouts are continually appearing, furnishing a direct com- 

 munication between the uninjured scale on the roots and the lower branches 

 of the trees. Thus the scale propagates on the roots regardless of any amount 

 of fumigation and supplies new broods for the orchards. Due to the protec- 

 tion of the soil the breeding continues throughout the winter as well as in the 

 summer. 



