The whiteflies or mealywing bugs, also referred to as aleyrodids, are small, inconspicuous, polyphagous insects often overlooked in spite of their abundance. Few species are also known to be vector of a number of virus diseases of crop plants. The economic importance of this group of insects has been well realized all over the world. There are many species causing substantial damage to agricultural and horticultural crops and forest trees and shrubs. The high economic status of these insects and lack of sufficient information of this group necessitated to bring into a single publication available details on their distribution, host plants and their influence on the morphological features of puparial cases, damage potential and management practices. As most of the species dealt with here are distributed worldwide the information would be of interest to applied entomologists.