on 
Southern California is separated by a range of mountains into a 
comparatively narrow fertile coast region and a dry interior valley, 
consisting of a high plateau, northward the Mohave Desert, and south- 
ward the low Colorado Desert, dipping in one place below the level of 
the sea. There is also an insignificant fertile strip along the Colorado 
River which is quite tropical. The coast region is the California 
mostly known to Eastern people. Here is where the great orange 
and lemon orchards are found. The summers are not as hot as are 
those of the great valley to the north, because of the influence of the 
ocean. Thus the shipping of early fruits is from the north to the 
south; even oranges, which ripen in winter, are being shipped from 
northern California fully a month earlier than from southern Cali- 
fornia. The insect fauna of this region is enriched by many Mexican 
forms, and differs strikingly from that of the great valley. Econom-. 
ically, most of their problems are as different as are their practices. 
The central portion of California, along the coast, consists of numer- 
ous valleys, each famous for the perfection of some product. The 
apple, prune, and wine grapes, for instance, are here at their best. 
South from San Francisco the insect fauna is very distinctive, with 
numerous peculiar local forms, some of considerable economic impor- 
tance, while north of the bay the fauna shades off on the one hand with 
that of the great valley, and on the other with the north coast region. 
The northern part of the State is mountainous or high lava beds. 
To the eastward and along the coast is a rather narrow fertile region 
having very heavy rainfall. Here dairy interests predominate. The 
fauna is practically the same as that of Oregon. 
To bring out more strikingly the economic significance of these 
divisions, let us now review some of the more injurious insects. 
SCALE INSECTS. 
Scale insects have attracted more attention in California than has any 
other group. The most injurious species at the present time is the 
black scale (Lecanium olew). In the south it is most troublesome on 
oranges and lemons, although it is also bad on olives and deciduous 
fruits. In the north it is injurious to olives and deciduous fruits in the 
coast valleys only, scarcely appearing in the great valley, which seems 
to be too dry for it. It is chiefly against this insect that fumiga- 
tion with hydrocyanic-acid gas is practiced, but only as it occurs on 
citrus trees. On deciduous trees resin-soap wash in winter is chiefly 
depended upon, but it is unsatisfactory on citrus trees. On these trees 
fumigation has come to be considered the only remedy. Some time 
ago a good deal of stir was made about the work of an Australian 
ladybird (22/azobius ventralis), and possibly all present may not know 
that it has in no way duplicated the results produced by the Vedalia 
cardimalis on the cottony cushion scale (Leerya purchasi). The other 
