240 



SUCKING INSECTS. 



lice have many enemies^ wliich cause an enormous dimintition in their 

 numbers. These insects are dealt with elsewhere (page 273). If we could 

 be sure that these enemies would attack the plant lice in time, Ave could 

 naturally check nearly every outbreak, but at present this is not possible. 

 These beneficial insects should be g-enerally familiar and on no account be 

 destroyed, 



The Mealy Wings (Aleurodidae). 



Small scale-like insects are frequently found upon plants, with small 



whitish flying insects which look 

 like very minute moths. These 

 are the insects known as mealy 

 wings, generally classed with the 

 scale insects and mealy bugs, from 

 which they are however quite 

 distinct. The young of both are 

 much alike in general appearance, 

 but if winged insects are found in 

 any numbers, the species is almost 

 certain to belong to this group. A. 

 number of species are known in 

 India vipon a variety of plants, and 

 though not common as pests they 

 are found and sent in for examina- 

 tion occasionally. 



JAfe History. — The female lays 

 eggs upon the plant, the eggs 

 usually enveloped in white cottony 

 material which she places upon the 

 leaf. These eggs hatch to small 

 insects which walk about the plant. 



Fia. 288. 

 Young Mealy Wings in scales. 



Each insect is very minute, scarcely visible to the naked eye ; it has a 

 beak which it pushes into the tissues of the plant in order to extract the 

 sap. Having found a good place it settles down and remains there until 

 it emerges as a flying insect. Each insect when settled down has the 

 appearance of a small scale, not more than one-tenth of an inch long ; 

 often they are black or dark-coloured Avith a fringe of white and some 

 white down over them. Others are brown or green, or are transj)arent 

 and not easily seen upon the plant. They remain fixed on the plant, often 

 in large numbers together. The juice of the plant is sucked out and the 

 plant itself weakened, The period during which they live thus varieg 



