160 INSECTS AFFECTING FLOWERS. 



like them have, when fully developed, four pairs of 

 legs. They multiply beneath their silken webs, 

 where one may find colonies of individuals (so small 

 as to be scarcely visible to the naked eye) in all 

 stages of existence. The young have but three pairs 

 of legs. The egg is very small and spherical, being 

 nearly colorless. The infested leaves assume a yel- 

 lowish hue, and many of them finally drop off. 



Remedies. — The Red Spider flourishes best in a 

 dry atmosphere. It is seldom troublesome in green- 

 houses where the air is kept saturated with moisture 

 and the plants are sprayed with water every day. 

 In window-gardens the plants should be sprayed 

 with soap suds, tobacco decoction or kerosene emul- 

 sion, or dusted with fine tobacco powder, as soon as 

 they show signs of the presence of this pest. 



Mealy-bugs and Scale-lice. 



Mealy-bugs are among the commonest and most 

 vexatious green-house pests. They occur upon a 

 great variety of plants, and reproduce freely through- 

 out the year. There are two or three species com- 

 monly found in this country, the most destructive, 

 perhaps, being the species called by entomologists 

 Dactylopius adonidum, which is distinguished by two 

 long, white, cottony threads extending backward 

 from the last segment of the abdomen. Another 

 common species is called Dactylojyius destructor. 



Mealy Bugs derive their oommon name from a 

 peculiar yellowish-white substance, resembling flour 



