514 CITRUS FRUITS AND THEIR CULTURE. 



on the under side of the leaves or upon the younger 

 twigs, especially in the forks. Ants are very industrious 

 agents in scattering them. The honey-dew excreted by 

 the mealy bugs forms the attraction for the ants which 

 care for them in a way that has been compared to the 

 attention man gives to his domestic animals. Free use 

 of carbon di-sulphide or scalding water in the nests of 

 the ants often furnishes the best means of controlling 

 the mealy bug. 



It feeds upon house plants, orange, coffee, tobacco, 

 croton, Ipomea, Learii, Habrothamnus, Pa3onia, Solanum 

 jasmoides and probably a number of others. 



Treatment. Use a powerful force pump and pene- 

 trating insecticide, such as kerosene emulsion, upon ma- 

 ture insects. Thoroughness and frequency of application 

 will govern the degree of success achieved in fighting 

 this insect. Repeated applications of potash whale-oil 

 soap, one pound in two or three gallons of water, made 

 while the insects are young will give most successful re- 

 sults. Limbs that are badly infested should have the 

 insecticide painted upon them with a brush or they may 

 sometimes be pruned out altogether. 



IV. SUCKING INSECTS OTHER THAN SCALES. 



The White Fly. (Aleyrodes citri Riley and Howard). 

 The egg is very minute, about 1-125 of an inch (0.2 mm) 

 in length, being attached to the leaf by a slender stem 

 or footstalk; about four times as long as thick, widest 

 just beyond the middle towards the free end; color pale 

 yellow, when first laid tinged with greenish, becoming 

 darker as the embryo develops and some specimens be- 

 coming of a dark steel gray or blue. Surface smooth and 

 shiny, often with clinging particles of white wax. Red 



