A FEW ORCHARD PLANT LICE 
C. P. GILLETTE AND E. P. TAYLOR* 
Among the worst insect enemies of the Colorado orchadist to¬ 
day are a few species of plant lice. The codling moth used to be 
our queen of orchard pests, but the apple growers have learned 
to successfully combat this insect by means of arsenical sprays. 
The plant lice, or aphids, illustrated and discussed in these 
pages, are not the only ones that fruit growers have to contend 
with, but they are the species needing the closest attention at the 
present time in Colorado orchards, and when one has learned to 
combat-these, he will be able to apply the proper remedies for 
the destruction of most other kinds that he is likely to come in 
contact with. It has been thought best to give a rather full account 
of the life habits of the lice here mentioned so that the fruit 
grower may belter understand the methods of control. 
The colored plates have been prepared at considerable expense 
that the reader may better recognize these pests. We believe the 
bulletin will help those who read it to understand that different 
plants have different species of lice infesting them, and that these 
lice often have very different life habits and require different means 
of control. The lice that infest any plant never appear spontane¬ 
ously, but every louse, like every higher or larger animal, is the 
offspring of a parent of the same kind. Consequently all the lice 
that infest our plants were either native, living upon Colorado wild 
plants before white men came here, or they have been carried to 
our orchards upon nursery stock from other parts of the world. 
GENERAL STRUCTURE AND HABITS OE THE PLANT LICE (Aphididae). 
There are a large number of species belonging to the group 
of insects commonly designated as ‘"aphids” or “plant lice,” 
vrhich have a remarkable similarity of structure and general habits. 
A knowledge of the more important structural characters of these 
*The general direction of the studies here repoirted, the determination 
of species, all descriptions, and many of the field and insectary records were 
made by the writer of this note. The extensive field experiments with 
remedies upon the Western slope, as well as many life history and food 
plant notes, were made by Mr. E. P. Taylor, while acting as Eield Entomolo¬ 
gist for this stlation. A large portion of the life history and food plant 
notes, both in the field and in the insectary, have been by Mr. L. C. Bragg. 
The illustrations are all by the department artist. Miss M. A. Palmer, with 
the technical descriptions before her. Miss Palmer always draws from her 
own measurements of parts and when her measurements and mine do not 
tally, we reach a joint agreement before she proceeds. So I believe the 
drawings will be found, structurally, quite reliable. 
The technical descriptions, with some additional notes upon life habits, 
have been sent to “Journal of Economic Entomology” for publication.—^C.P. 
GILLETTE. 
