Body parts of workers were cut so as to expose tissuessufficiently to penetration ofchemicals used during tissueprocessing for histological examination.Cutsweremadetoobtain anterior heads, posterior heads (with prothoraxattached), posterior thorax (with petiole and anterior gasterattached) and posterior gaster. Tissues were fixed in cold2% glutaraldehyde, buffered at pH 7.3 with 50 mMNa-cacodylate and 150 mM saccharose and postfixed in2% osmium tetroxide in the same buffer. Dehydration wascarried out in a graded acetone series. Araldite-embeddedtissue blocks were sectioned with a Reichert Ultracut Emicrotome. Semithin 1-lm sections were stained with