ANTENNAL SENSILLA OF WHITEFLIES - TRIALEURODES-VAPORARIORUM (WESTWOOD), THE GLASSHOUSE WHITEFLY, AND ALEYRODES PROLETELLA (LINNAEUS), THE CABBAGE WHITEFLY, (HOMOPTERA, ALEYRODIDAE) .2. ULTRASTRUCTURE

A transmission electron microscope study of the antennal sensilla of t he whitefly Trialeurodes vaporariorum and Aleyrodes proletella (Homopt era: Aleyrodidae) revealed that of the sensilla unique to the antennal flagellum (basiconic, coeloconic and small digitate-tipped sensory pe gs), basiconic and coeloconic sensilla occur as subtypes. Four subtype s of basiconic cone sensilla occur on the flagella of T. vaporariorum and 3 on A. proletella. All the subtypes of basiconic sensilla have an ultrastructure typical of olfactory sensilla and probably have a prim ary olfactory function. Two subtypes of coeloconic sensilla occur on t he flagella of both species. Their ultrastructure suggests primarily a chemosensory function. The digitate-tipped sensory peg of both specie s possesses a triad of neurones which have ultrastructural characteris tics similar to the known thermo-/hygroreceptors of other insect speci es. The other sensilla, which occur on the antennae of the whiteflies, include cheatae, campaniform and subcuticular sensilla, all of which have an ultrastructure typical of mechanoreceptors.