88 THE MONTHLY BULLETIN. 



Food Plants. — All species of citrus trees, camellia, Oleo straiissia 

 and coffee. 



Natural Enemies. — This insect would be a far greater pest were it 

 not for its many natural enemies. Two internal parasites. Aphidius 

 iestaceipes Cress, and Charips xanthopsis, have been bred from adalt 

 lice, while the California ladybird beetle {Coccinella califoniica) and 

 the larva? of three syrphid tiies {Allograpta ohliqua Say, Syrphus 

 americanus Wied. and LasiopMMcus pyrastri Linn.) were observed in 

 large numbers feeding upon the lice. 



COCCID.E (Family). 



SCALE INSECTS. 



To the California horticulturist, and especially to the citrus 

 grower, the scale insects are by far the most destructive and persistent 

 pests. More money is spent in combating them than all other insects 

 together. 



Many members of the family have the ability to produce a scale-like 

 covering, from whence the name scale insect comes, while others, 

 though unable to form a scale, secrete a hardened chitinous shell ; while 

 still others secrete an abundance of white, cottony wax for protective 

 purposes. 



The young are either born alive or from eggs previously laid by 

 the female. They always have legs, enabling them to move about 

 freely. In many species the legs are retained throughout the entire 

 life cycle, enabling the adults to move as freely as the young, but in 

 the scale-bearing species the legs disappear in the females, there being 

 but a small body under the shell, while in the case of the males the 

 moults are undergone under the scale, the adult appearing as two- 

 winged, very delicate insects. 



Control. — The control of scale insects has long been one of great 

 importance throughout the entire country. Formerly only sprays 

 were used in combating them, l)ut during the past few years fumiga- 

 tion, especially in the citrus growing sections of the state, has become 

 the principal control method. Scale insects occurring on deciduous 

 fruit trees are most efficiently and cheaply controlled hy the use of 

 sprays, and the mealy bugs on citrus and other trees are also sub.jected 

 to a similar treatment. All armored scales as well as such unarmored 

 scales, as the black and soft-brown, on citrus trees are most effectively 

 controlled by fumigation. 



Natural Enemies. — One of the most noted examples of the control 

 of a serious insect pest by natural enemies is that of the cottony 

 cushion scale, Icerya purchasi, by the Vedalia, Novius cardinalis. 

 Other ladybird beetles and internal parasites also form an important 

 part in the control of scale insects, being responsible for the complete 



