ALMONDS—APHIDS 45 
First, to select varieties that are pro- 
lifie bearers, for some varieties will not 
bear fruit enough to pay the cost of ecul- 
tivation. 
Second, to select varieties that cross pol 
linate, for most varieties of the almond 
will not pollinate from the same tree. 
Third, to select a site for the almond 
orchard that is as nearly as possible free 
from frost, because the tree is an early 
bloomer and the fruit buds are tender. 
There are about 25 varieties grown in 
California and the general treatment and 
cultivation given to them is simular to 
that given to the peach. 
The almond is propagated by budding 
on seedling stock, and at maturity the 
nuts are gathered some time in the au- 
tumn. The kernels should be smooth, 
plump and symmetrical in order to bring 
the highest price in the market. 
Almonds Produced in the United States 
There are but few states in the Union 
which produce almonds for commercial 
purposes. The number of bearing trees 
by states, as reported in the census of 
1910, gives California 1,166,730; Arizona, 
6,639; Utah, 1,408; Nevada, 18. We per- 
sonally know of a few trees in Washing- 
ton, and doubtless there are in many other 
states a few grown for home use. The in- 
dustry in the other states, however, has 
not assumed commercial importance. 
Varieties 
The more important varieties are as 
follows: 
California, California Jordan, Chilinese, 
Commercial, Drake, Eureka Jordan, Gol- 
den State, I. X. L., Languedoc, Lasser, 
Nonpareil, Prolific, St. Joseph, Texas. 
GRANVILLE LOWTHER 
ALTITUDE. 
ing Site For. 
See Apple Orchard. Select- 
ANTHRACNOSE, TIME TO SPRAY For. See 
San Jose Scale on Apple, under General 
Recommendations. See also Black Spot 
Canker. 
Aphids 
The Aphididae or plant-lice are among 
the largest families in the great Order 
Hemiptera. Economically they rank 
among the groups of the higher impor- 
tance and few indeed of the higher plants 
there are that are not subject to their 
attack. Many of our most injurious forms 
on fruit trees and truck crops were im- 
ported from Europe, while indigenous 
species include the grape Phvylloxera, first 
imported from wild American vines into 
France and later from that country into 
the grape regions of California. Aphids 
feed solely by means of a stout beak 
which they thrust into the plant tissue 
and through which the juices of the plant 
are Sucked up. In certain species this 
sucking mode of feeding causes the plant 
tissue to form galls or pseudo-galls in 
which the lice continue to dwell pro- 
tected from their foes. Certain other 
species live on the roots of trees or small 
plants, but the great majority exist un- 
protected on the leaves, stems or flower- 
heads of their food-plants. Many aphids 
—and among these are a number of very 
injurious forms—migrate at certain 
periods from one host plant to another 
and such hosts may be widely separated 
botanically. Our knowledge of these 
migrations and the causes which pro- 
duce them is as yet far from complete. 
Most aphids are confined to one host or 
to several closely related plant species, 
but a few forms, as for example the 
Green Peach Aphis (Myzus persicae 
Sulz.), attack a large number and variety 
of plants. Parthenogenetic reproduction 
occurs in the vast majority of aphids, al- 
though true sexual forms are produced in 
most species once a year, the sexual fe- 
male after copulation with the male de- 
positing winter eggs. In some species, 
especially those inhabiting evergreen 
plants, it is thought that two or more 
years may elapse between appearances of 
the sexed forms, as these forms have 
failed to appear when expected. Parthen- 
ogenetic females are winged and wing- 
less, in some species only the former. 
Sexed males and females may be winged 
or wingless, according to species. Lab- 
