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derived from more or less intuitive classifications,in which adult and immature stages oftaxa may appear to show different phyleticaffinities. The method requires a great numberof char.acters to be studied. Consequently,Srether's descriptions include a largearray of character statements and his paperstaken together are an extraordinary loadedseries of data. The value of these data is furtherincreased by their mostly homogenousand consistent presentation.Cladistic analysis means searching forevolutionary trends and interpretation foreach cladogenetic level which characters areprimitive (plesiomorphic) or derived (apomorphic).In one major opus after another Sretherpresented resolved cladograms from largeand complicated data matrices. Ofparticularimportance was his classification of chironomidsubfamilies where, for the first time inchironomid systematics, the information displayedby female adult morphology was usedin classification. Srether had prepared theground himself to make this possible. In astudy of female genitalia, he described andfigured more than 200 species ofchironomidsand other nematocerous Diptera and he outlineda terminology of female genital structures.When he presented this broad comparisonof morphological differentiation of femalegenitalia, two major achievements weremade. First, it revealed good prospects for thepossibility of identifying the previously neglectedchironomid females and nowadays,descriptions of females generally form an integralpart of chironomid species descriptions.Secondly, new sets of characters wereavailable to be used in cladistic analyses. Theimpact of this on chironomid systematics wassignificant, resulting among other things in areevaluation of the relationship between chironomidsubfamilies.Another work ofsignificant impact on chironomidsystematics was Srether's glossary tochironomid morphological terms. This compilationof terminology with recommendedterms and their synonyms has certainly madelife easier for the chironomid systematist andthe paper was an important step towardsstandardization and homogenization of chironomiddescriptions. This particular worktogether with the recently elaborated keys tothe Holarctic genera of chironomids, towhich Srether has made significant contributions,will probably give a greater number ofentomologists and freshwater biologists accessto and guidance through the labyrinthsof chironomid systematics.Although the study of systematics is anautonomous disipline and has become a fulltime committment in itselffor Srether, he hasnot forgotten his basic training as a limnologistand his initial motivation for enteringinto systematics. The «Seetypen Lehre» developedby Thienemann and his followersculminated when Srether in 1979 publishedhis more refined means of characterizingtrophic levels of lakes from the compositionof their chironomid communities. To the extentthat these methods have been used theyhave sometimes proved to be more informativethan physio-chemical analyses in detectingecological changes and sources of pollution.Through his detailed studies of a great varietyof chironomid groups. Srether has reacheda level of overview as well as detailedinsight into manifestations of evolutionarydifferentiation that probably few systematistsshare with him. His experience derivedfrom analyses ofmorphological variation in ahighly complex taxon and his practical applicationof phylogenetic systematics has madehim believe that the interpretation of apomorphiesand plesiomorphies is less straighforwardthan originally anticipated in phylogenetictheory. Accordingly, in several of hismore recent publications he has advocatedthe idea of «underlying synapomorphism», aconcept introduced by L. Brundin as «insideparallelism». He has also defined what heconsiders a necessary distinction between«objective synapomorphies» and «subjectivesynapomorphies». Objective synapomorphiesmore or less correspond to the orthodox definitionof synapomorphies. Underlying synapomorphiesbehave in an analogous mannerto recessive genes and are regarded as apotential capacity to develop a certain character.These ideas are controversial amongadherents ofphylogenetic systematics and byraising them Srether has provoked disputeand theoretical confrontation in internationaljournals.Nevertheless, the issues focusedhere by Srether are undoubtedly of great importancein clarifying the theoretical basis ofany attempts to reconstruct coherent phylogeneticsystems. Srether claims that all kindsofcharacter sets must be taken into account inthe total evaluation of genaeological relationshipsbetween taxa. Although one maydisagree with his conclusions, his way of pre­2