22 



is a rather rich reddish, often obscured fjy extraneous matter taken 

 from the surface of the leaves or bark. It apparently requires a great 

 deal of moisture to thrive well, and hence is apt to be abundant on 

 oranges or other plants grown in conservatories, and this also accounts, 

 doubtless, for its greater multiplication and injur}'^ in Florida than on 

 the Pacific coast. 



Breeding continues practically throughout the year. According to 

 Hubbard, there are three periods in Florida when the young are espe- 

 cially abundant, marking in a rough way the appearance of the main 

 broods, namely, in March and April, in June and July, and in Septem- 

 ber and October; the fourth, irregular brood, occurring in January 

 or Februar3^ 



The treatment for this scale is the use of the oily washes and fumi- 

 gating with hydrocyanic-acid gas. It is much more easily controlled 

 than the purple scale. 



The Purple Scale. 



The original home of the purple scale {.MytilaspiscitncolaFsLcka.Yd) 

 (figs. 10 to 12) is unknown, but it now occurs practically wherever 



Pig. 10.— Purple scale {Mytilaspis dtricola), showing different .stages of female: a, newly hatched 

 larva; b, same with first waxy secretion; c to/, different stages of growth; g, mature scale; h, same 

 inverted, showing eggs; i and j, half-grown and full-grown female insects removed from scale — all 

 mucli enlarged (original). 



the orange or lemon is grown. It was probably introduced into this 

 'country at an early date. It is frequently associated with the long 

 scale, and is one of the most troublesome scale insects affecting the 

 orange and lemon, because it is very difficult to get an application on 

 the trees strong enough to kill all of its eggs with one treatment. 

 For many years the purple scale was limited in this country to Florida 

 and the Gulf region, but some years since it was carried on Florida 

 stock into southern California, where, fortunately, it has not yet 

 become widely distributed. In general color it is a brownish purple, 

 and in shape duplicates the oyster-shell scale of the apple. The life 



172 



