172 NATURE TEACHING 



small beetles called weevils, and others have a liking 

 even for cigars and cigarettes. 



Green Fly. 



Every gardener is sure at some time or other to 

 have his attention called to another group of insects, 

 "green fly," or plant lice. These are often found on 

 young shoots and buds, and if nothing is done to check 

 them they increase enormously, and the leaves on which 

 they are often curl up, wither, and die. Green fly are 

 provided with a beak or proboscis, which they thrust into 

 the plant and use to suck up its juices. Each green fly 

 is very small, but they often occur in such countless 

 numbers that together they do a great deal of harm 

 to the plant. Although usually called green fly some 

 are black ; for instance, the plant lice often found on 

 beans. 



The presence of green fly is often indicated by a 

 sticky deposit on the leaves of the plants, which some- 

 time trickles down the stems or drops on the ground. 

 This sticky liquid is called " honey dew," and is produced 

 by the green fly. In London the lime trees are often 

 attacked by green fly, and the honey dew dropped by 

 them forms damp patches on the pavement, so that 

 walking along and watching the pavement you can 

 often tell that you are passing under a lime tree and 

 that the tree is attacked by green fly. 



Rose-growers are often troubled by finding the 

 leaves of their plants disfigured by having pieces cut out 

 of them as neatly as if done by a sharp knife. The 

 offenders are certain biting bees which cut out these 



