ENTOMOLOGY 259 



greenhouses. Females are viviparous, but the generations are not 

 well marked. Soap and water or kerosene emulsion will readily de- 

 stroy these scales at any season of the year. 



White Scale; Oleander Scale. This scale is a pest of green- 

 houses, where it attacks oleander, croton, ivy, palms, camellia and 

 many other plants. It is nearly circular in shape, and white or light 

 grey in color, making it conspicuous on the green leaves and stems. 

 It probably breeds continuously in greenhouses. Fumigating the 

 house with hydrocyanic acid gas, spraying the infested plants with 

 either whale oil or common soap (1 Ib. in 8 gallons of water) are 

 the remedies for this scale. 



Circular Scale: Fig Scale. Rubber plant, orange, palms, camel- 

 lias and oleander-in greenhouses .are often infested by a round diark- 

 colored scale which stands out prominently from the surface of the 

 leaves. In fact" it is almost conical in shape, reddish brown or nearly 

 black, with an orange apex. Presumably it continues to breed 

 throughout the year under glass, and continued spraying is necessary 

 to keep it in check. 



Red Orange Scale. A light grey or brown circular scale about 

 2 mm. in diameter occurring on oranges and lemons in the markets 

 and sometimes infesting citrus trees and palms in greenhouses. The 

 scale is somewhat translucent, showing the reddish insect beneath. 

 The female is reniform in shape. This scale causes 1 much injury in 

 th'e orange groves of California, and also occurs in Florida. (Fifth 

 Report of the Entomologist, Conn. Agr. Exp. Sta.) 



Morgan's Scale. It is of about the same color as the preceding 

 species, but is flatter, and projects only slightly from the leaf. Mr. 

 H. E. Hodgkiss studied this scale at the Massachusetts Agricultural 

 College, and found that several generations are produced each year, 

 but these overlap so as to become indistinct. The females bring forth 

 living young, are parthenogenetic, and males are unknown. Fumi- 

 gating the house with hydrocyanic acid gas, using 7.5 grams potas- 

 sium cyanide for each 100 cubic feet of space, for forty minutes, after 

 dark, with the plants free from moisture, is the treatment advised by 

 Mr. Hodgkiss after making many experiments. It is probably a safe 

 remedy for nearly all of the greenhouse scales. (Fifth Rep. Ent. 

 Conn. E. S.) 



Mealy Bugs.* These are probably the most universally distrib- 

 uted and well known of all greenhouse pests. No florist, and but few 

 housewives, attempting to maintain a window garden, but are famil- 

 iar with them, to a greater or less degree. Two species occur in 

 Maryland. 



The Short-spined Mealy Bug. This bug, in the adult form, 

 is about 4 mm. in length and 2 mm. in width oval or elliptical in 

 outline, with a fringe of short spines encircling the body. Those 

 spines are thirty-four in number, and of about equal length, those 

 on the anal end of the body being slightly longer than the others. 

 The body is covered with a white waxy mass, giving (lie insect its 

 common name of mealy bug. If 'his wax is removed the body is seen 

 to be of a brownish color. 



* See illustration on page 195. 



