APPENDIX. 373 



Female, third stage — After the second molt the females still appear pale 

 yellow as before, with various larger and smaller transi)arent spots around 

 the border of the body. The form is nearly circular with greatest diameter 

 averaging lifty-six one-hundredths of a millimeter. The sucking bristles 

 are very pi'ominent and long, three times the length of the insect. The last 

 segment in this stage has practically the characters of the mature female, as 

 follows : There are two pairs of lobes, the terminal ones largest and nearly 

 three times as broad as the other lobes. Terminal lobes are rounded at the 

 apex and are distinctly notched near the middle of the external edge. The 

 second pair of lobes is smaller and narrower and is also notched externally. 

 Between the first and second lobe on either side is a small spine and two or 

 three such spines are just back of the second lobe, while back of these are 

 three stout teeth, curving anteriorly. A still smaller blunt tooth sometimes 

 occurs near the middle of the lateral margin. The segmentation of the body 

 at this stage is quite distinct. 



Jfature female — After reaching maturity the embryonic young are at first 

 not visible, but later the body becomes filled with them. The mature female 

 measures eight-tenths of a millimeter wide by about one millimeter long.* 



The following description of this stage is reproduced from Comstock : 



'• The body of the female is yellowish and almost circular in outline ; the 

 segmentation is distinct, though not conspicuous. The last segment presents 

 the following characters : 



•'There are only two pairs of lobes visible : the first pair converges at tip. 

 are notched about midway their length on the lateral margin, and often bear 

 a slight notch on the mesal margin near the ti]). The second pair are notched 

 once on the lateral margin. 



"The margin of the ventral surface of the segment is deeply incised twice 

 on each side of the meson: once between the t)ases of the first and second 

 lobes and again laterad of the second lobe. On each side of each of these 

 incisions is a club-shaped thickening of the body wall. 



•'There are two inconspicuous simple plates between the median lobes, 

 and on each side similar plates extending caudad of the first incision, three 

 small plates serrate on their lateral margin caudad of the second incision, 

 and the club-shaped thickening of the body wall bounding it, and three wide 

 prolongations of the margin between the third and fourth spines. These 

 prolongations are usually fringed on their distal margins. There are also, 

 in some, irregular prolongations of the margin between the fourth spine and 

 the penultimate segment. 



■•The first and second spines are situated laterad of the first and second 

 lobes, respectively : the third spine laterad of second incision : and the 

 fourth spine about one-half the distance from the fourth lobe to the penulti- 



mate segment. 



MEANS OF DISTRIBUTION. 



From an economic standpoint, the important considerations in the means 

 of spread of this insect are those which affect its wide distribution from one 

 part of the country to another. The transportation by nursery stock or 

 scions, or budding and grafting material, as indicated in the foregoing 

 account of this insect, is unquestionably the usual and principal means of 



*Rept. U. S. Dept. Agric, 1S.S0, p. :»l. 



