Wax secretions in Bemisia tabaci (Hemiptera : Aleyrodidae). Evolution during the larval cycle.

Adults and larvae of Bemisia tabaci Gennadius are covered with wax. The pro duction of this wax was studied in scanning electron microscopy in the male and the female adults and during the larval development. In the adults, th e wax is secreted at the level of sieves resulting from the regrouping of n umerous pores located on the abdominal sternites. It appears banded and is filamentous. It is spread by the combs of the tibiae of the posterior legs and is fixed on the integumental microstructures of all parts of the body o f the insect. In the larvae of the four stages, it is secreted by two types of wax-producing pores. Several tens of geminate-type pores scattered over the whole dorsal surface secrete the wax that covers all the dorsal area. Two simple-type pores located on the ventral side of the posterior part of the abdomen secrete the filamentous wax forming fences on the lateral edge.