314 GKEENHOTJSE MANAGEMENT. 



nation, lily and azalea. As a remedy, the hose should be 

 used freely on bright days, and if this does not suffice, 

 it is well to make free use of whale-oil soap, kerosene 

 emulsion, or evaporated sulphur. The vapor of tobacco 

 can also be used with good effect, as can Paris green. 

 When they have become imbedded in the flowers, the 

 buds should be picked off and burned. Heliothrips 

 Jicemorrlioidis, Bowd, is sometimes quite troublesome 

 upon crotons, and Coleothrips trifasciata, .Fitch, is 

 another troublesome greenhouse species. 



SCALE INSECTS. 



Although at first these insects have but little resem- 

 blance to the aphides to which they are closely related, 

 a careful comparison of the different organs will show 

 that in many important particulars the resemblance is 

 quite marked. 



The simplest forms of these insects are the mealy 

 bugs (Fig. 110), so-called from the fact that they cover 

 themselves with a white cottony 

 substance. The female mealy 

 bug, one of the most common of 

 which is Dactylopius adonidum 

 (Linn. ) Signoret, does not change 

 its form, and except in size is 

 much the same in appearance at 

 all stages. When about to lay its 

 eggs, it attaches itself by means of 

 its beak to the surface of a leaf, 

 or stem, secretes a mass of long, 

 cottony, tuft-like particles of wax 



FIG. 110. MEALY BUG. V ,i , • . ,, , ■■ 



around the tip of the abdomen, 

 beneath which the eggs are deposited. In addition to 

 this, the antennae, legs and each segment of the body 

 have shorter appendages. From each lateral segment 

 they appear as short bristles, while those at the rear end 



