Acta Zoologica 23. (1977)

1977 / 3-4. szám - STYS, P.: Revision of Symphylax (Heteroptera: Colobathristidae)

REVISION OF SYMPHYLAX 42<J Wallace’s sense); however, no speciesoccur on the Philippine Islands. patterns of distribution known at the present timecan he tabulated, as foil S. confluens confluens+ V S. confluens borneensis+ S. curvispina S. ghaurii— S. handschini+ — S. musiphthora+ S. picticollis9 + S. wallacei S. walshi So far it seems that each species has a very limited range and I have seen material of no taxon from more than only one major territory. Unfortunately, Symphylax species are rarely present in collections, and I have not been able to prover or disprove Horvath’s (1904) records of occurrence of some taxa (S. confluens on Sumatra, S. picticollis on Borneo) beyond their typical terri­tories since the material has not been available. However, since Horvath's specific criteria were too rough, these records seem doubtful. Taxonomic value of characters, a) Somatic characters. Symphy­lax species are structurally very uniform and their somatic characters are of limited value for diagnostic purposes. Critical examination of the available material shows that most of the somatic characters used hy Ghauri (1968) in his key are subject to variation, and that reliable identification is in most cases possible only when based on the study of the genitalia. Second antennal segment is longer than third in Symphylax walshi, shorter in all other species; the ratio length II : III may be sometimes used for discrimination between certain couples of species (e. g. between S. ghaurii and S. picticollis), but the extent of its variation is unknown in other species known from only a few specimens. Both Kormilev (1953) and Ghauri (1968) separated Symphylax hand­­schini and S. walshi from other species on the basis of their short labium. However, I have found that Kormilev’s (1953) data on the shortness of labium in these species were slightly exaggerated and that a similarly short labium, reaching only to the apices of mesocoxae, may also occur in S. confluens and S. curvispina. The length of labium considerably varies in all species where larger material has been examined, and the ranges of variation in species with a moderately long labium overlap both with those possessing short labium and with that of S. ghaurii, a species with the longest labium (always reaching at least between the bases of metacoxae). Symphylax confluens sharply differs from all other species by a great extent of dark coloration on the vertex and posterior lobe of pronotum. It has been thought that the absence of dark humeral spots distinguishes Symphylax walshi and S. picticollis var. blandus (status uncertain) from the other species. Malaya Borneo Sumatra Mentawei Java — , -f-— Acta Zoologica Acadcmiae Scientiarиm Hungaricae 23, 1977

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