69 
The alatc viviparous female {Vl. III., Fig. 1) is 4 to 5 mm. long, 
with an occasional maximum of 6 mm., and 1 to 1.5 mm. broad. An- 
tennae long, reaching to the tip of the stylus or a little beyond; first 
and second segments short and close to the tubercle; third to sixth 
segments related in length respectively as 3 : 2: 1.5 : 4, the terminal fila- 
ment of the sixth segment being three times as long as the base. Wing 
expanse about 11 mm. Fore wing 5 mm. by 2 mm. Cornicles slender, 
cylindrical, and long, — 1 to 1.5 mm. Abdominal stylus half as long as 
the cornicles. 
Sanderson gives smaller measurements thruout for the autumn 
winged viviparous female, it being only 3.15 mm. in length, with pro- 
portions varying a little from those just given. 
The apterous viviparous female (PI. III., Fig 2) is a little larger 
than the winged female, ranging in length from 4 to 6 mm., and the 
body is more elongate and fusiform, with longer cornicles (1.25 to 2 
mm.) and a longer stylus. This form also is smaller in autumn, as 
Sanderson has noted, with much more extensive dark brown or black- 
ish markings on the appendages. 
The oviparous female is apterous. 
The egg has not been described before. It is elliptical, twice as 
long as broad (0.5 mm. by 0.25 mm.), and changes from saffron-yellow 
to shiny black one or two days after being laid. 
The zvinged male is 2.5 mm. in length, with a wing expanse of 9 
mm. It may be recognized by its smaller size, among other things. The 
color tends toward pale green or yellow. The dorsal sclerites are dark, 
as is also the mesosternum, and there are lateral blackish spots in front 
of the cornicles. Sanderson has described this form. 
Our insectary notes on one pair of M. pisi taken in coitu refer to 
the male as being apterous. 
In autumn many of the aphids normally turn yellow; in fact, 
some yellow individuals can be found at any time, and aphids that are 
diseased usually do become yellow. 
Life History. — The clover-louse winters both as a large wingless 
viviparous female and as an egg, but the eggs are not numerous. 
Many of the females are killed off during the winter. The survivors 
are easily found under rubbish in the clover field in the first week 
of April and even as early as March 25, tho.they are a little slow to 
revive. They crawl to the clover plants and proceed to suck the sap 
and to bring forth living young, all of which are also females ; indeed, 
no males appear until the last of the season and no eggs are laid until 
then. During most of the season there is nothing but a constant suc- 
cession of females, all of them born alive. Most of them are wingless, 
tho in any of the generations there may be some females that have 
wings; these also bear their young alive. 
The eggs that were laid on green leaves or stems the preceding au- 
tumn hatch a few days after the red clover starts on its new growth. 
March 23 Mr. E. O. G. Kelly found newly hatched young on a clover 
plant, and egg-shells close by on old dead clover leaves. One of these 
aphids, kept on potted clover, produced her first young April 5, and 
died May 12, after having brought forth ninety young. 
