S. Mahunka szerk.: Folia Entomologica Hungarica 32/2. (Budapest, 1979)
strongly that they have been described as representatives of a single species - without, however, correctly recognizing the cause of the phenomenon. The first* such "dimorphic" description goes back to VITZTHUM (1927) who figured the pentamerous and tetramerous (leg I) forms correctly but without making any remarks or expressing his opinion concerning this difference (or if at all recognizing it? ) (MAHUNKA, 1975). In the course of rearing populations obtained from dung, I have already assumed the conspecificity of Siteroptes priscus (Krczal, 1959) and Pediculaster mesembrinae (R. Canestrini, 1881) without, however, having been able to prove it unconditionally. From a Brazilian soil sample, I described aPygmephorid species and genus (Pediculitopsis tubiphorus Mahunka, 1969) with penta- and tetramerous legs I, very similar to Resinacarus , but considered the relationship of the two forms as nymph and female, respectively. SMILEY et MOSER (1975) were the first who correctly recognized, and also unequivocally proved by rearing, the conspecificity of the pentamerous (in their terminology: "normal - Siteroptes 1 and tetramerous ("phoretom orphie - Pediculaster) forms, as well as the fact that they both represent females. They explained the existence or occurrence of the two forms primarily by causes inherent in their life-history. Shortly thereafter (CROSS et MOSER, 19 75), polymorphism was proved in both sexes also in a Pyemotid species (Pye mote s dimorphus Ci oss et Moser, 1975), though it showed less evident morphological differences than in the also Pyemotid Resinacarus or in Pediculaster of another family. These excellent works had therefore unquestionably proved the intraspecific existence of two morphologically distinct males or females also in the Tarsonemid group. By their studies of the crucial genus Siteroptes Amerling, 1861, RACK (19 72) and SUSKI (1973) have also considerably contributed to the clarification of the problem. Investigating the ontogeny of the species Siteroptes "gramineum Reuter, 1900", RACK also recognized the existence of two female types: although they show no essential morphological differences, their life-histories are sharply distinct. And on the basis of painstaking morphological observations SUSKI demonstrated that Siteroptes "gramineum " can be separated in to several well distingui'shable but hitherto multiply confused and misinterpreted species; the characteristic and distinguishing features of the species and genus became thereby much more clearly recongizable. Since our knowledge of the Tarsonemids is still very incomplete - despite the increasing amount of publications in recent years - it was inevitable that false conclusions have occasionally been drawn from the new data. Without undertaking any extensive investigation, MOSER et CROSS (1975), then SMILEY et MOSER (1976), inferred from the existence of the two female types, apparently belonging in two extant genera, that the "Siteroptes" form can unconditionally be relegated to the genus Siteroptes Amerling, 1861, with the resultant logical conclusion of having drawn in, as a junior synonym, the genus Pediculaster Vitzthum, 1931, because of the existence of the phoretomorphic "Pediculasteroid" form. They have, however, failed to take into consideration the fact that the genus Siteroptes was less than homogeneous also in earlier times and that subsequent - and pertinent - splittings have also been attempted (Metasiteroptes Cross, 1965**, Siteroptoides Cross, 1965, Tesiroptes Mahunka, 1969). In addition, they simply synonymized even their own genus, Pygmephorellus Cross et Moser, 1971, with Siteroptes , although the "phoretomorphic" female and also the male of the former display such utterly different features even when compared to the species of the genus Pediculaster that their assignment to a single genus is impossible. SUSKI' s preceding work, probably unknown to the authors cited above owing to the closeness of the publication dates, has incontestably shown that the species-group " gramineum" , or now correctly " cerealium " group, has nothing much to do with the species-group There is a possibility that already BERLESE surmised the correct relationship of two forms. I found some slides in the BERLESE Collection in Florence (Coll. Berlese: box 26, slides 30-32) designated as " Pigmephorus mesembrinae var, aardous Berl. o", containing exclusively "siteroptid" forms, although BERLESE interpreted the species P. mesembri nae R. Canestrini, 1881, correctly. 'Transferred to the family Pyemotidae by MAHUNKA in 1970.
