196 INSECTS INJURIOUS TO VEGETATION. 



used warm and applied with a watering pot or with a garden en- 

 gine, may be employed for the destruction of these insects. It is 

 said that hot water may also be employed for the same purpose 

 with safety and success. The water, tobacco-tea, or suds should 

 be thrown upon the plants with considerable force, and if they are 

 of the cabbage or lettuce kind, or other plants whose leaves are to 

 be used as food, they should subsequently be drenched thoroughly 

 with pure water. Lice on the extremities of branches may be 

 killed by bending over the branches and holding them for several 

 minutes in warm and strong soap-suds. Lice multiply much 

 faster, and are more injurious to plants, in a dry than in a wet 

 atmosphere ; hence in green houses, attention should be paid to 

 keep the air sufficiently moist ; and the lice are readily killed by 

 fumigations with tobacco or with sulphur. To destroy subter- 

 ranean lice on the roots of plants I have found that watering with 

 salt water was useful, if the plants were hardy ; but tender herb- 

 aceous plants cannot be treated in this way, but may sometimes 

 be revived, when suffering from these hidden foes, by free and 

 frequent watering with soap-suds. 



Plant-lice would undoubtedly be much more abundant and de- 

 structive, if they were not kept in check by certain redoubtable 

 enemies of the insect kind, which seem expressly created to 

 diminish their numbers. These lice-destroyers are of three sorts. 

 The first are the young or larvas of the hemispherical beetles 

 familiarly known by the name of lady-birds, and scientifically 

 by that of Coccinella. These little beetles are generally yellow 

 or red, with black spots, or black, with white, red, or yellow 

 spots ; there are many kinds of them, and they are very common 

 and plentiful insects, and are generally diffused among plants. 

 They live, both in the perfect and young state, upon plant-lice, 

 and hence their services are very considerable. Their young are 

 small flattened grubs of a bluish or blue-black color, spotted 

 usually with red or yellow, and furnished with six legs near the 

 forepart of the body. They are hatched from little yellow eggs, 

 laid in clusters among the plant-lice, so that they find themselves 

 at once within reach of their prey, which, from their superior 

 strength, they are enabled to seize and slaughter in great numbers. 

 There are some of these lady-birds, of a very small size, and 



