There are in Britain three species of gall midges the larvae of which may be found in pea-pods: the pea midge (Contarinia pisi, Winn.), which is the most common and is sometimes a pest; Lestodiplosis pisi, Barnes, a predator on the former; and Clinodiplosis pisicola, sp. n., an inquiline. The larvae are readily distinguishable both by their colour and by the structure of their anal extremities (fig. 1).