‘26 
longest; fourth and fifth subsequal and about equal to the thickened ' 
proximal part of the sixth. Cornicles short, tapering towards the 
tip, not swollen, extremities flared. Cauda short and wide. Length 
of body, 1.4 mm.; width of body, .93 mm.: antennae, .57 mm. 
The young of this form are paler in color and have proportionally j 
longer rostra and shorter cornicles. 
Winged viviparous female [aerial form].—Head black. Thorax 
chiefly black above. Abdomen pale green, faintly bluish at sides, 
with three marginal black spots on each side preceding larger spots 
which surround the bases of the cornicles. Antennae chiefly black, 
Cornicles black. Cauda green, edged with black. Segments behind 
the cauda dark-edged. Head and thorax beneath chiefly black, 
Abdomen pale green, with two transverse black marks preceding the 
cauda. Legs pale at their articulations; middle part of tibiae often 
pale. Rostrum chiefly black. Body more slender than that of the 
female of the root form. Antennae rather long; fourth and fifth 
articles each longer than the basal part of the sixth. Cornicles 
moderately long, swollen in the middle. Length of body, 2 mm.: 
width of body, .87 mm.; antennae, about .85 mm.: cornicles, .2 mm.: 
wing, 2.65 mm. 
Pupa of winged viviporous female [aerial form].—Head dark brown, | 
often presenting an appearance of two longitudinal dark "bands. 
Body chiefly pale green. Wing-pads, cornicles and tip of cauda 
black. Antennae chiefly dark. Beak dark at base and tip. Legs 
nearly all dark; tibiae pale proximally. Length of body. 1.6 mm.; 
width of body, .62 mm.; antennae, .7 mm.; cornicles, .12 mm. 
Wingless viviparous female [aerial form].—General color pale green, 
with cauda, cornicles and greater part of the rostrum, antennae, and 
legs black. Head with two broad, approximated, longitudinal dark 
bands which give the prevailing color. Abdomen with the usual 
marginal black spots and the black patch about the base of the 
cornicles. Antennae dark at base and apex. Eyes reddish brown. 
Anterior legs mostly pale. Rostrum dark at base and apex. More 
slender than the female of the root form and of a brighter green 
color. The cornicles are swollen in the middle. Length of body, 
1.97 mm.; width of body, 1 mm.; antennae, .75 mm.; cornicles, 
.17 mm. 
The young of this form differs from the adults in the same manner 
as do those of the root form, i. e. they are more slender, have 
longer beaks and shorter cornicles. 
Towards fall the green color worn by the adults is changed for 
darker colors and often females which are still giving birth to young 
are bluish black. A meal-like coating can be detected on the bodies 
by examination with a lens. 
LIFE HISTORY AND HABITS. 
Naturalists hold to the belief that it is not in accordance with 
natural law that a species of animal should reproduce indefinitely 
without the union of the male and female sexes. It is true that 
when supplied with heat and food artificially, certain species of 
Aphides have been induced to reproduce for long periods without 
