366 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 1 



pear and Crataegus; but also, to some extent, upon the clovers, and in 

 some cases upon Bursa, as alate apterous and viviparous females and 

 young, when given sufficient protection and when the weather is not 

 too cold. The stem females hatch very early, so that many are fully 

 grown and giving birth to young by the time the apple buds begin 

 to open. The fully developed stem-mother is usually rather dark 

 red in color. 



Winged spring migrants begin to appear in considerable numbers 

 in the second generation, and are abundant in the third generation. 

 By June 30, they have nearly all left the trees, but small colonies do 

 sometimes continue thi'oughout the season upon the apple. The spring 

 migrants go to the clovers as their summer host plants, and the female 

 fall migrants begin returning to the apple, pear and Crataegus about 

 the last of September. A little later the alate males which develop 

 upon the summer food plants, follow to fertilize the apterous oviparous 

 females, which are the offspring of the fall migrants. The oviparous 

 females begin to deposit eggs about October 20. ]\Ir. George P. Wel- 

 don reported finding the first eggs at Delta. Colorado, on October 26. 

 and states that they are at first green like the eggs of Aphis pomi, 

 but soon become black. 



The striking characters Avhich readily separate this species from 

 others that infest the apple and pear are the light yellow to pink color 

 of the body in the larvae and apterous adults ; the minute dark specks 

 which occur upon the dorsum of the apterous forms, both larvae and 

 adults ; the large dark green to blackish quadrate patch upon the dor- 

 sum of the alate forms ; and the short cornicles. In case of the larvae 

 and apterous lice there is also a light area at the base of each cornicle 

 which is often quite conspicuous. 



During last spring this louse was the most abundant species upon 

 the apple and pear trees on the western slope in Colorado. 



Adult Stem-Mother— Plate 9, figs. 1 and 5. 



Specimens taken at Eckert, April 11, 1908. 



Gi'ound color darl< green at first, and more or loss streaked and mottled 

 with deep red both above and below, but there is much more red on the dor- 

 sal than on the ventral side; cornicles and cauda very short and pale yel- 

 lowish green, almost colorless; legs and antennae pale green, with distal ends 

 of the tibiae and antennae and the tarsi black; general form rather long and 

 tapering posteriorly when just mature; old lice more robust and nearly all 

 dark red, even legs, prothorax and antennae in some cases; length of body 

 about 1.90 mm.; antenna .70 mm.; joints: III, .37; IV, .13; V, .11 mm. 

 There is some variation in length of antenna and in some cases joint 3 is 

 divided into two making 6 joints. In some cases there will be 5 joints in one 

 antenna and 6 in the other on the same louse. Near the end of joint 3 (or 



