Data on the diet of the web-invading spider Mimetus notius were collected to determine the diet of this araneophagic spider. Mimetus notius primarily invades Theridiidae and Aaraneidae webs and is capable of preying upon at least seven families of spiders, principally in the genus Theridion (Araneae: Theridiidae). Mimetus notius invades the webs of several species on which no successful predation was observed. These data provide the first field data showing significant insectivory by a web invading mimetid, constituting 29% of the prey in this study. The presence of insects in the diet provides a potential explanation for the invasion of webs where successful predation on the resident is unlikely.