This paper is primarily aimed at describing new species and subspecies identified through the rearrangement of the African Butterfly Research Institute (ABRI) collection material and in the course of research for Larsen’s book project butterflies of West Africa and their Natural History.  A number of interesting species and subspecies procured by Haydon Warren-Gash are also included.  The following species and subspecies are described – Lycaenidae: Ornipholidotos stempfferi, O. dowsetti, O. kivu, O. nancy, Iolaus (Epamera) longicauda haydoni, Iolaus (Iolaphilus) caesareus cleopatrae, Iolaus carolinae, Hypokopelates viridis parellela; Nymphalidae: Cymothoe althea bobi, Acraea oreas oboti; Hesperiidae: Celaenorrhinus nimbi, Ceratrichia lewisi, and Paracleros staudei.  Subspecies are only described when there are substantial morphological differences that have a biogeographically plausible basis.  An error in the description of the genitalia of Ornipholidotos jacksoni Stempffer, 1961 is shown to be a junior subjective synonym of E. magnimacula Rebel, 1914.  Paracleros substrigata is identified as a senior subjective synonym of P. overlaeti.   

Mkomazi Game Reserve* encompasses a semi-arid, physiographically diverse savanna incorporating a broad habitat spectrum, from open grassland through Combretum bushland and Acacia-Commiphora woodland to Afromontane forest. A preliminary and largely opportunistic survey recorded 153 butterfly species within the reserve.  Based on distribution and habitat preferences we estimate that as many as 419 species may eventually be recorded as occurring in Mkomazi.  This is a high species richness for a savanna area the size of Mkomazi, and underlines the important role the reserve plays in conserving a representative portion of the diverse East African butterfly fauna.  The topographic and associated habitat diversity contributes towards the presence of a number of different biogeographical elements within the reserve.  Three distinct assemblages are discernible within the Mkomazi butterfly community.  The commonest assemblage constitutes species associated with Carcasson’s Eastern Zone of Open Formations, typically including species with a widespread distribution covering eastern and southern Africa.  The remaining two assemblages represent more specialized communities.  The Afromontane forest element (Carcasson’s Tanzania-Nyasa Zone of Highland Forest) is restricted to less than 1% of the reserve.  However, relative to area, the montane forest habitat contains the highest butterfly species richness within Mkomazi and needs to be carefully managed from a conservation perspective.  Carcasson’s Somalia Zone of Open Formations provides the assemblage most characteristic of the reserve, one whose species are associated with arid scrub and dry grassland of the Somalia-Masai regional centre of floral endemism.  A number of new distribution records were documented during the survey.  Mkomazi is the northern most locality that Alaena nyassa major has been recorded, and populations of Belenois margaritacea intermedia and Acraea cerasa cerasa were unexpectedly located within the reserve .  A species previously only known from Kenya, Acraea pudorina, was recorded for the first time from Tanzania.  We also report on the role that butterflies play in Acacia pollination ecology within Mkomazi.  Butterflies along with bees and flies are important pollinators of a number of Acacia species within the reserve.