Pomona College Joihinal op Entomology 799 



occasionally get them to walk by detaching one gently from the leat'-surfaee, 

 or may even (rarely) find one walking of its own accord, but they now move 

 slowly and unciTtainly, in distinetion to their brisk movements when they first 

 emerge from under the old shell. 



Before they have settled down for the first time they are 0|)a(iue, but once 

 settled they seem very quickly to become transparent, with the alimentary 

 canal showing through as a darker streak down the middle, and two whitish 

 streaks on each side extending from this median line to the edges of the scale. 

 I believe these white streaks are caused by grooves on the under surface. The 

 general color of the scale at this age is light green, but it is so transparent as 

 to be almost indistinguishable from the leaf-surface with the naked eye. The 

 shape is a blunt oval. The eyes show up as minute black dots. There is a 

 deep, slit-like anal cleft. They resemble most the young of the Soft Brown 

 scale, but are transparent and green, rather than yellow and opaque, and lie 

 flatter on the leaf, appearing to adhere closely to it like a mere film, while the 

 young of the Soft Brown is thicker and the central portion more raised, so as 

 to be convex, or dome-shaped. 



As they grow older they become more yellowish, and begin to retire from 

 the leaves onto the twigs. By the end of January I have found this migration 

 almost completed, though a few will occasionally be found to have stayed on 

 the leaf till death. On the twigs they soon lose their yellowish tinge, and 

 assume a sort of dull, mottled gray color (very different from the glazed ap- 

 pearance and yellowish or light brownish color of the hesperidum). They are 

 now no longer flat or film-like, but convex in profile, oval in outline, and soft 

 to the touch. (I think "Soft Gray scale" would be a good descriptive popular 

 name for this scale.) 



The full-grown scales would probably attain a length of about three-six- 

 teenths to one-fourth inch. I have never found them on the fruit, nor on 

 twigs thicker than a cedar pencil. I have found them on every kind of citrus 

 tree, but not on any other. They are arranged on the twigs, when they occur 

 in large numbers, in a characteristically imbricated manner, like fish-scales, 

 and being now all in the. adult stage, they look very different from the indis- 

 criminately arranged masses of all sizes which is characteristic of hesperidum. 



Death — Soon after the hatching begins the surface of the mother scale 

 becomes dry, and light brown in color, and begins to adhere less closely to 

 the twig. When the young are all born the shell is very apt to drop off, leav- 

 ing a whitish mark. One does not often find old shells of the year before, as 

 is the case with the black scale. The whitish mark referred to is formed by 

 the debris, apparently, of some envelope which must invest the young before 

 birth, for a little pile of this debris is always found under the old shell along 

 with the new-born young. 



Smut — This scale throws out a great deal of honey-dew, the resulting 

 smut making the trees very dirty. The earliest date I have observed the 

 honey-dew is April 20. As a rule, it does not smut up the trees till the navels 

 are all picked, but the Valencia fruit becomes much soiled. 



