A great diversity of arthropods is symbiotically associated with army ant colonies. Despite the efforts of several generations of researchers to survey army ant symbiont diversity, many species still await scientific discovery. Moreover, the taxonomy of many army ant-associated groups remains unsettled. Here we re-assess the species status of two army ant-associated beetles of the family Histeridae (subfamily Haeteriinae): Ecclisister bickhardtiReichensperger, 1923 and Ecclisister bickhardti costaericaeReichensperger, 1935. We examined specimens fromCosta Rica, Panama, Ecuador, Peru, Guyana, and Brazil. Based on the analysis of external and genital morphological characters, we elevated the subspecies to species level. In addition to morphological characters, we provide 11 DNA barcodes for E. costaericae, new status, to facilitate future identifications. A survey of symbiont diversity of the six local army ant species of Eciton Latreille at La Selva Biological Station, Costa Rica, revealed a specific association of E. costaericae with the host ant Eciton burchellii foreliMayr, 1886. We describe the beetles' mechanism of phoretic transport and discuss reasons for the many taxonomic ambiguities in army ant symbionts.