S. Mahunka szerk.: Folia Entomologica Hungarica 31/1. (Budapest, 1978)

FOLIA ENTOMOLOGICA HUNGARICA ROVARTANI KÖZLEMÉNYEK (SERIES NOVA) XXXI. 1. 1978 p. 199-203 Contribution to the knowledge of the species Aradus ribauti Wagner, 1955 (Heteroptera: Aradidae) By T. VÁSÁRHELYI (Received November 22, 1977) Abstract: Description of the larval instars II to V of Aradus ribauti Wagner, 1955, with remarks on the larval growth and biology of the species is given. Its occurrence in Romania is reported for the first time. Aradus ribauti described some twenty years ago is one of the less known European Aradus species as far as its distribution and biology are concerned. Consequently, it was interesting to find flowering populations of the species on some dead trunks of Populus alba attacked by tinder fungus on a sandy area of the Great Hungarian Plain (Fülöpháza and Ágasegyháza, near Kecskemét in the territory of the Kiskunság National Park). Since the betulaegroup of closely related species has several problematic questions every detail is a valuable contribution towards a better understanding of their relations. Additional data on distribution: By the kind loan of B. KIS (Cluj, Romania) I could identify one exemplar of A. ribauti (Craiova, 28. VI. 1964, leg. B. Kis). Thus, this species also occurs in Romania. Larval development: The materials examined were collected several times in field and numerous exemplars were reared on tindery pieces of bark kept in glass vessels and watered in every 2-3 days, respectively. The populations were consisted of different larval instars in each case. Adults were observed in copula at the end of April and in the first days of May. In this time only instars IV and V larvae were found. The eggs were deposited under the bark or in laboratory on the reverse of the bark, or in hidden places, e.g. into splits of the bark, one by one, rarely two or three at a time. At the end of May no living imago but many instar II larvae were observed. At the end of July in field mostly instar V larvae were found while in the population brought in on the 3rd. May even living imagos were represented amongst the mostly instar III larvae. Laboratory rearing thus proved useless for investigations as regards time, however, no significant morphological differences have been found. In autumn (6 October) two kinds of populations were found in field. The first comprised only imagos, the second, geographically near to the former, contained of instars III to V larvae and imagos

. The bugs in field were ordinarily sitting on the underside of the trunk even in the case when the upper parts were tindery or under the bark, respectively (each trunk was lying on the ground).