Abstract1Published records of the hosts ofN.canescenshave been collected and critically examined.2It is accepted thatcanescenshas developed on twenty‐three species; on one of them perhaps accidentally, on two with some doubt.3Twelve species were parasitized in nature; nine species in the laboratory. Two species served as hosts when artificially infected.4The natural hosts belong in the Pyralidae, Tinaeidae and Yponomeutidae; the laboratory hosts in the Pyralidae, Oecophoridae and Gelechiidae. One individual was reared from a Tortricid, perhaps accidentally.5The host specificity ofN.canescensis not easily explained on either a systematic or an ecological basis. It offers interesting problems for researc