Abstract. The paper deals with descriptions of four new species of Archostemata from the Paleocene and Earliest Eocene amber, Cupes manifestus n. sp., C. orbiculatus n. sp., C. ponomarenkoi n. sp. and Micromalthus eocenicus n. sp., the latter representing the oldest member of genus Micromalthus Leconte 1878 (Micromalthidae). The position, composition and origin of the genera Cupes and Micromalthus are considered. Cupes seemed to appear during Cretaceous or very close to this period, while Micromalthus could originate somewhat later. The synonymy of Cupedini and Priacmini is grounded. The genus Crowsoniella Pace 1975 (Crowsoniellidae) could be excluded from the suborder Archostemata and transferred into the infraorder Cucujiformia (Polyphaga). Résumé. Nouveaux Archostemata du

The proportions of the different bibionid genera are used to estimate the temperature changes between the Late Eocene and the Late Miocene in Western Europe. The genus Plecia is a good indicator of the warm Cenozoic palaeoclimates. We propose a new approach for the estimation of the value of the palaeoclimatic information that could be obtained by actualistic inferences using extinct taxa. Other taxa (i.e. Mastotermitidae) that could appear a priori better palaeoclimatic indicators result to be less sensitive than bibionids to temperature changes. Intraspecifi c and intrageneric morphological diversity is explored for the genera Bibio, Penthetria and Plecia, showing the diffi culties to characterize the fossil bibionid species. Résumé. Les Bibionidae et le climat cénozoïque européen (Diptera).Les proportions des différents genres de Bibionidae sont utilisées afi n d'estimer les changements de temperatures entre l'Eocène terminal et le Miocène terminal en Europe de l'Ouest. Le genre Plecia s'avère un bon indicateur des paléoclimats chauds au Cénozoïque. Nous proposons une nouvelle approche d'estimation de la valeur des informations paléoclimatiques qui peuvent être obtenues par des inférences actualistes basées sur des taxons éteints. Des taxons (Mastotermitidae) qui peuvent apparaître a priori comme des indicateurs paléoclimatiques plus évidents que les Bibionidae sont en fait moins sensibles que ces derniers aux changements de température. La diversité morphologique intraspécifi que et intragénérique est explorée pour les genres Bibio, Penthetria et Plecia, montrant les diffi cultés de caractérisation des espèces fossiles dans cette famille.

The Diptera fauna from the late Eocene of the Isle of Wight (Bembridge Marls) is studied including redescriptions of formerly described material. The fauna includes the following taxa: Anisopodidae – one species; Bibionidae – 11 species; Ceratopogonidae – one described and two unidentified species; Chironomidae – undetermined species of three subfamilies; Culicidae – four species; Cylindrotomidae – one species; Dixidae – one species; Keroplatidae – one described and four unidentified species; Limoniidae – 31 species; Mycetophilidae – 14 species; Psychodidae – two species; Scatopsidae – two species; Sciaridae – three species; Simuliidae – an unnamed species; Tipulidae – nine species. Diptera Brachycera: Agromyzidae – unidentified species; Anthomyzidae – two species; Asilidae – two species; Bombyliidae – one species; Chloropidae – one species; Dolichopodidae – unidentified species; Empididae – unidentified species; Ephydridae – two species; Heleomyzidae – unidentified species; Lauxaniidae – unidentified species; Otitidae – one species; Phoridae – unidentified species; Rhagionidae – two species; Stratiomyidae – two species; Syrphidae – unidentified species; Tabanidae – one species. Following new taxa are described: Leptotarsus (Longurio) fragmentatus Krzemiński, n. sp., Leptotarsus (Longurio) wegiereki Krzemiński, n. sp., Tipula (s. lato) anglicana Krzemiński, n. sp. (Tipulidae); Cyttaromyiarossi Krzemiński, n. sp. (Cylindrotomidae); Gurnardia corami Krzemiński, n. gen, n. sp., Pilaria hooleyi Krzemiński, n. sp., Pilaria volodii Krzemiński, n. sp., Cheilotrichia (Cheilotrichia) duplicata Krzemiński, n. sp., Cheilotrichia (Empeda) szwedoi Krzemiński, n. sp., Symplecta (Psiloconopa) gurnetensis Krzemiński, n. sp., Orimarga (Orimarga) lenae Krzemiński, n. sp., Dicranomyia (Dicranomyia) azari Krzemiński, n. sp., Dicranomyia (Dicranomyia) fasciata Krzemiński, n. sp., Helius (Helius) edmundi Krzemiński, n. sp., Helius (Helius) popovi Krzemiński, n. sp., Dicranoptycha staryi Krzemiński, n. sp. (Limoniidae); Wightipsychoda Azar, n. gen. (Psychodidae); Dilophus andrewrossi Nel, Colomb & Waller, n. sp., Bibiodes massiliensis Nel, Colomb & Waller, n. sp. (Bibionidae); Azana cockerelli Blagoderov, n. sp., Aglaomyia vectis Blagoderov, n. sp., Dziedzickia oligocenica Blagoderov, n. sp., Palaeoempalia saxea Blagoderov, n. sp., Mycomyahoolei Blagoderov, n. sp., Leia gurnardensis Blagoderov, n. sp. (Mycetophilidae); Regmocleminahaennii Krzemiński, n. sp. (Scatopsidae); Sylvicola problematica Krzemiński, n. sp. (Anisopodidae); Palaeoberidops barkeri Nicholson, n. gen., n. sp. (Stratiomyidae). The Diptera fauna and palaeohabitat of the Insect Bed is discussed.