184 Bugs, Cicadas, Aphids, and Scale-insects 



FIG. 252. The San 

 Jose scale, Aspidiotus 

 perniciosus. a, male; 

 b, adult female. 

 (Much enlarged.) 



with the natural reddish green of the uninjured bark. With the second 

 moult the females do not change materially from 

 their former appearance, retaining the pale-yellow 

 color with a number of transparent spots around 

 the edge of the body. The sucking-bristles are 

 extremely long, two or three times the length of the 

 body of the insect. 



"About twenty days after birth the male insect 

 transforms to the true pupa. With the first moult 

 the shed larval skin is retained beneath the scale 

 as in the case of the female; with the later moult- 

 ings the shed skins are pushed out from beneath 

 the scale. The scale, after the second moult, pre- 

 sents on the inside two longitudinal ridges run- 

 ning from one end to the other, touching the sides 

 of the pupa, and which apparently enable the 

 insect to move backward or forward and assist the imago in pushing itself 

 out. 



"The true pupa is pale yellow, sometimes purplish, darkened about 

 the base of the abdomen. The head, antennae, legs, wing-pads, and style 

 are well formed, but almost colorless. ... 



"From four to six days later, or from twenty- four to twenty-six days 

 from birth, the males mature and back out from the rear end of their 

 scales, having previously, for a day or two, remained practically developed, 

 but resting under the scale. They seem to issue chiefly by night or in 

 the evening. 



"The mature male (Fig. 252) appears as a delicate two-winged fly-like 

 insect with long feelers and a single anal style projecting from the end of 

 the body; orange in color, with a faintly dusky shade on the prothorax. 

 The head is darker than the rest of the body, the eyes are dark purple, and 

 the antennae, legs, and style are smoky. The wings are iridescent with 

 yellow and green, very faintly clouded. 



"Thirty days from birth the females are full grown and the embryonic 

 young may be seen within their bodies, each enclosed in a delicate mem- 

 brane. At from thirty-three to forty days the larvae again begin to make 

 their appearance. 



"The adult female, prior to the development of the young, measures 

 one millimeter in length and a little less in breadth, and is pale yellow with 

 transparent spots near the margin of the body (Fig. 252). 



"The length of a generation is determined by the female, and, as shown 

 by the above record, covers a period of from thirty-three to forty days. Suc- 

 cessive generations were followed carefully throughout the summer, and 



