cape, leaving only a brown hard shell 
where once was an aphis. In Florida, 
other parasites of somewhat similar 
habits have been bred from cabbage 
aphides, and called respectively Allo- 
tria brassicse* Encyrtus aphidiphagus 
and Pachyneuron aphidivora; 
Very frequently ants will be seen 
running round a colony of plant lice, 
and it is known that they aie there 
fCfc^he purpose of collecting the 
swSrt \ excretion of the aphides, of 
which they, are extremely bond. 
Charles Darwin has written an inter- 
esting account of this as follows: 
“One of the strongest instances of an 
animal apparently performing an ac- 
tion for the sole go15d of another, 
with which I a up acquainted, is that 
of aphides voluntarily \iclding, as was 
first observed by Huber, their sweet 
excretion to ants: that they do so 
voluntarily, the following facts show. 
I removed all the ants from a group 
of about a dozen aphides on a dock 
plant, and prevented their attendance 
during several hours. After this in 
terval, I felt sure that the aphides 
would want to excrete. I watched 
them for some time through a lens, 
but not one excreted; I then tickled 
and stroked them with a hair in the 
same manner, as well as I could, as 
the ants do with their antennae, but 
not one excreted. Afterward I allow- 
ed an ant to visit them, and it imme= 
d lately seemed, by its eager way of 
running about, to be well aware what 
a rich flock it had discovered: It 
then began to play with its antennae 
on the abdomen first of one aphis and 
then of anothei; and each, as soon as 
it felt the antennae, immediately lifted 
up its abdomen and excreted a limpid 
drop of sweet juice, which was eagerly 
devoured by the ant. Even the quite 
young aphides behaved in this man- 
lier, showing that the action \yas in=- 
stinctive, and not the result of ex- 
perience. It is certain, from the ob- 
servations of Huber, ih^t the aphides 
show no dislike to the ants; if-the lat 
ter be not present they are at last 
compelled to eject their excretion. 
But as the excretion is extremely vis- 
cid, it is no doubt a convenience to 
the aphides to have it removed; Pere* 
fore they probably do not excrqte 
solely for the good of the ants.” 
As to remedies for the cabbage 
aphis, fumigation with tobacco smoke 
has been recommended, but is not of 
much practical use. A strong solu- 
tion of whale-oil soap is said to be 
very effectual, while one writer rec- 
ommends sprinkling with soap-suds 
treated with quassia. Dr. Riley con- 
siders^that the application of kerosene 
emulsion will prove the most satisfac- 
tory remedy. 
Many other species of plant lice oc- 
cur in Custer county, such as the 
Quaking Asp Aphis, the Bigelovia 
Aphis, and the Gymnolomi^i Aphis — 
10 
