32 



The Hemispherical Scale. {Saissetia hemisphoerica Targ.) 

 This is usually the most common soft scale found in greenhouses. 

 It is a brown "lump" in form, rather less than a fifth of an inch long, 

 and nearly as broad, and is found on many kinds of plants though 

 most abundant on palms, ferns and cycads. It locates both on the 

 leaves and stems, and in Massachusetts seems to be particularly 

 abundant on the Boston fern. Its life history does not seem to have 

 been completely worked out, but it probably breeds at all seasons 

 of the year, laying eggs which hatch into rather flat, pale-colored 

 young. 



The Soft Scale. {Coccus hesperidum Linn.) 

 This scale is similar to the last, but the young are apparently born 

 alive. It feeds on citrus plants, oleanders and many other green- 

 house plants. 



The White Scale. {Aspidiotus hederx Vail.) 

 The white scale has also quite a list of food plants, but is perhaps 

 as abundant on the ivy, palms and croton as any in Massachusetts 

 greenhouses. It is quite flat, having only a slight elevation at or near 

 the center, is circular in outline, and is white or light gray in color, 

 sometimes with its central elevation orange-yellow. It lays eggs from 

 which adult scales are produced in about two and a half months, but 

 the different generations run into one another, so that almost all 

 stages may be found at any time. 



Morgan's Scale. {Chrysomphalus dictyospermi Morg.) 

 This important pest on palms is circular in outUne, dark colored, 

 usually with an orange spot near the center, and is quite flat, pro- 

 jecting only very slightly from the leaf. The young are born alive, 

 and males are unknown. There are several generations in a year, 

 but, as was stated for the white scale, these run into each other or 

 overlap. 



Mealy Bugs. 



Two kinds of mealy bug are met with in greenhouses, the more 

 common one having a fringe of spines around the body, the two at 

 the hinder end being somewhat longer than the others. In the less 

 common kind these hinder spines are much longer, — sometimes as 

 long as the body. In both the body is more or less covered with a 

 white, waxy substance, which has been the cause of their receiving 

 the name "mealy bugs." 



The several hundred eggs laid by the female are carried under the 

 hinder end of the body, and as these are laid the insect tips upward 

 till it is almost standing on its head. When egg laying has been 

 completed the parent dies, and after about two weeks' time from the 

 laying of the first eggs these hatch. The newly hatched young are 

 quite small, not covered with the wax, and after a time they move about 

 and begin feeding, which continues for six or eight weeks before they 

 become adult, sucking the juices from the plants they are on. 



Mealy bugs feed on many plants, but perhaps the oleander, coleus, 

 some palms and citrus plants are preferred members of the list. 



