S. Mahunka szerk.: Folia Entomologica Hungarica 57. (Budapest, 1996)

ROVARTANI KÖZLEMÉNYEK LVII 1996 pp. 277-284 Female internal genitalia of Megalithone tillyardi Riek, 1974 with comments on the systematic position of the neuropterous families (Neuroptera: Ithonidae) Gy. Sziráki Female internal genitalia of Megalithone tillyardi Riek, 1974 with comments on the systematic position of the neuropterous families (Neuroptera: Ithonidae) — Investigations were carried out on the ectodermal parts of the female internal genitalia (FEIG) of Megalithone tillyardi. This is the first ithonid species examined in detail in this respect. The results of our studies on FEIG of an ithonid species, and those of the additional investigations on larval antennae of different families offered possibility for establishing homologies in these systematically important structures of Neuroptera. The synapomorphies recognized on the basis of the newly established homologies support in many respect the systematic scheme used conventionally. Female internal genitalia (FEIG) of insects usually have great taxonomic and phylogenetic importance, since their basic structure is rather conservative, while some of their details often show species specificity (Sziráki 1996). The family Ithonidae — with prognathous head, complete, primitive wing venation, broad hind wing, 5 larval instars — is usually regarded as the most archaic extant group of the order Neuroptera (Withycombe 1925, New 1991). Consequently, an investigation of FEIG of this family promised important data to judge the systematic position of the other neuropterous families as well. For this reason studies were carried out on female specimens of M. tillyardi collected by C. N. Smithers and G. F. Smithers at Tuglo, 48 km N of Singleton, New South Wales, Australia. The method of FEIG investigations basically was similar to those described in earlier works (Sziráki 1992), however, some structures also were checked after a short time (2 minutes) of boiling with 5% KOH (instead of 10% KOH, 5 minutes duration), or boiling in lactic acid (instead of KOH). In course of a short survey of the neuropterous families, in addition to the evaluation of the characteristics of FEIG, the structure of the larval antennae also was taken into consideration because of the great phylogenetic importance of the larval features, and of the relatively large independence of the antennái characteristics from the habit of life. Description of FEIG of Megalithone tillyardi (Figs 1-2) Vagina elongated. Its wall moderately chitinized, however, strong, leather-like with wrinkled surface. Bursa copulatrix is rather large, in dorsal view its shape rounded sub-