Hoverflies of the subfamily Microdontinae (Diptera: Syrphidae) have a reputation for causing confusion. Their diversity in shape and size is astonishing: from large, furry-haired species and... Show moreHoverflies of the subfamily Microdontinae (Diptera: Syrphidae) have a reputation for causing confusion. Their diversity in shape and size is astonishing: from large, furry-haired species and convincing wasp-mimics to tiny, unsightly creatures, easily mistaken for something uninteresting. The larvae resemble slugs so much that biologists have described them as molluscs on several occasions. Worldwide, hundreds of species of Microdontinae have been described, but so far there has been no comprehensive attempt to unravel this hotchpotch of names. This thesis examines the phylogenetic relationships of Microdontinae, based on morphological and molecular characters, in order to construct a new classification of the subfamily. A total number of 51 (sub)genera (11 new) are recognized, in which 472 valid species (49 new) are classified, resulting in many new combinations. The newly proposed classification facilitates species level taxonomy. In addition, it should provide a framework for further research on biogeography, (cryptic) speciation and evolution of host specialization. This thesis takes a first shot at some of these subjects by exploring the taxonomy of Neotropical Microdontinae that mimic stingless bees, reviewing and evaluating the associations of these flies with ants, and speculating on their historical biogeography. Show less