The insect collection comprises around 700,000 specimens, divided approximately into half British and half non-British. These are housed separately in taxonomic sequence for each Order, in unit trays and slats in standard drawers.
The British collection contains a comprehensive representation of the Orders Lepidoptera (butterflies and moths), Coleoptera (beetles), Diptera (true flies), Hemiptera: Auchenorrhyncha (leafhoppers, planthoppers etc), Heteroptera (true bugs) and Hymenoptera: Aculeata (bees and wasps). It has good representation of most other groups. The policy towards the British collection is to develop as near a complete British collection as possible, in all groups.
Notable British collections include H.M. Hallett (Coleoptera and Aculeate); A.E. Gardner (Coleoptera); J.R. le B. Tomlin, B. MacNulty, part of the W.J. Le Quesne & F.J. Coulson Hemiptera Collection & M.F. Claridge.
The non-British collection includes significant holdings of insects from all Orders from many regions, which are used for teaching demonstrations at various levels. Besides general Lepidoptera, there are also important holdings of Coleoptera, Diptera and Hemiptera, which have developed through the research interests of the staff members. The specimen acquisition policy concentrates on the Palaearctic, as well as the Afrotropical regions, although for research interests the focus may be wider.
Notable collections (other than those made by the staff) include the R. Linnavuori Hemiptera collection from the middle East and Africa and a part of the J.A.J. Simpson collection of medically-important flies.
The research strengths of the Entomology Section centre around taxonomic and faunistic work on Diptera (especially Muscidae, Agromyzidae and Chloropidae), Hemiptera: Auchenorrhyncha and Coleoptera. Further detail is given under 'Staff'.