Description of Immature Stages of Two Neotropical Species of Plecia, with a Discussion about the Evolution of Immature Characters in Bibionidae (Insecta, Diptera, Bibionidae)

Abstract The oviposition behavior, eggs and first three instar of Plecia cf. collaris (FABRICIUS) and the eggs, last larval instar, and the pupa of Plecia plagiata (WIEDEMANN) are described. This is the first information on immatures of Neotropical Bibionidae. It is also the first description of the egg and pupa of a Neotropical species of Plecia , and the second larva described of the genus. The evolution of a number of characters concerning oviposition behavior and morphology of egg, larvae, and pupae of Bibionidae is proceeded. Character polarity is obtained by outgroup comparisons. The generality of the characters is given in a phylogeny of the group.