218 



APPLIED ENTOMOLOGY 



The Hemispherical Scale {Saissetia hetnispharica Targ.). — This scale is 

 usually found in greenhouses and on house plants, such as ferns, palms, orna- 

 mental asparagus, etc., and also out of doors in the South. It is very convex, but 

 rather oval than hemispherical, about one -eighth of an inch long, brown in color. 

 The partly grown young are very flat and with a notch at the hinder end. The 

 eggs are laid during about a 3-month period in late spring, thus resulting in the ap- 

 pearance of young during a long time. Fumigation 

 as for the Black Scale, or dipping the plant in whale- 

 oil soap 1 lb., water 2 gal., and after an hour rinsing 

 the plant by dipping it in water, are fairly effective 

 treatments. 



Mealy Bugs 



Mealy Bugs move about more or less freely 

 during their life, as their limbs are not lost to 

 any extent by degeneration. Nor is a scale 

 present, the body being generally well covered 

 by long, waxy threads, though in some cases 

 waxy secretions forming plates connected with 

 the body are produced. 



These insects are inhabitants of warm cli- 

 mates and in the North are found only in green- 

 houses and on house plants. 



Fig. 214. Fig. 215. 



Fig. 214. — Cottony Maple Scale {Pulvinaria vitis L.), about half natural size. 

 (Modified from Felt, N. Y. State Mus. Mem. 8.) 



Fig. 215. — Citrus Mealy Bug {Pseudococcus citri Risso.), enlarged. 



The Citrus Mealy Bug {Pseudococcus citri Risso). — This insect attacks many 

 plants and is a serious pest on citrus plants, feeding on the roots, stems, leaves 

 and fruit, gathering in large clusters on the last. It produces a large amount of 

 honey-dew, on which the sooty fungus already referred to grows. The adult 

 females, pale yellow in color and well covered by a th ck waxy secretion (Fig. 215), 

 are one-fourth of an inch long. The 300 to 500 eggs are laid in loose, white cotton- 

 like masses, chiefly during fall and winter, and young and adults move about 

 freely, the former becoming adult before the following summer. The cottony wax 

 covering the insects renders them particularly difficult to reach with sprays. 

 The best spray thus far found is a carbolic acid emulsion. To prepare this take 

 8 gal. of water and boil, adding 8 lb. of soap. After this has dissolved, add 1 lb. 

 crude carbolic acid and boil 15 to 20 min., which will give a thick, creamy emul- 

 sion. To spray, dilute 1 gal. of this with 20 gal. of water. Spray between 



