The present-day composition and distribution of diaspidid scale and coccinellid beetle species in the Pacific is an amalgam of endemic distribution, and naturalisations or extirpations following unintentional accidental dispersal as well as intentional dispersal as part of biological plant pest control measures. Using primary sources, historic biogeography not only allows us to untangle the nature and sequence of introductions but also to assess which species have endured. This paper is a case study of early twentieth century coccinellid beetles introductions to Micronesia. When faced with the spectre of a collapse of the local copra industry on Yap, the German colonial administration in Micronesia embarked on an ambitious program to eradicate, or at least contain the coconut scale insect. To this end numerous species of coccinellid beetles were introduced from within the Western Pacific (Saipan, New Britain) as well as from the outside (Australia, China, Philippines).