With 2 plates and 12 figures in the text) Within the Astigmata, setal homologies with the general chaetotaxic systems developed for acariform mites by F. Grandjean have never been convincingly established. This study deals with all body regions, exclusive of legs and gnathosoma, mostly utilizing as models astigrnatid species from three different families. Six hypotheses which attempt to explain the ontogeny of segments, setae and cupules in the caudal bend region are compared using three-dimensional views obtained by scanning electron microscopy. The hypotheses are evaluated by in-group comparisons testing their consistency with presumed segmental boundaries, and by out-group comparisons with oribatid mites. The strongest, most parsimonious hypothesis suggests that larval astigmatid mites possess segment F, but not its setae, and the two pairs posterior to segment Fare hl and h2, whilst the five setae added in the protonymph are h,, f2 and psi-3. Six pairs of structures on the deutonymphal anal plate are identified as modified setae, and evidence supporting their homologies with setae of other instars is discussed for the first time. A comparison of the principal chaetotaxic systems used for the dorsal and anal regions of the Astigmata is presented. Application of Grandjean's setal signatures to these regions, as well as to the coxisternal and genital regions, is discussed and illustrated by examples.

Electron-dense particles of melanin were located in ultrathin sections of: the hyphal walls of Amorphotheca resume; the aleuriospore walls of Epicoccum nigrum and Humicola grisea; the sclerotial walls of Colletotrichum coccodes; and both within and between the microsclerotial cell walls of Verticillium dahliae. Melanin was extracted with KOH from each of the fungi, but, because of rapid oxidation of the pigment in air, extraction and analysis was carried out under nitrogen. The pigments were examined spectrophotometrically under UV and IR radiation and by means of x-ray diffraction. Characterization of the melanin in terms of its degradation products indicated it to be indolic in nature. These results are compared with published data on other melanins extracted from animal and plant sources.

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