New geographical records and key to the species of Eumerus Meigen, 1823 (Diptera, Syrphidae) introduced into the Americas and Hawaii

Abstract Eumerus Meigen, 1823 is a very speciose genus of flower flies from the Eastern Hemisphere. Several reports of introduced species of this genus in the Americas have been recorded since early in the twentieth century, with a present list of six species recorded to date from the Americas and the US territory of Hawaii. In this paper we give new geographical records for the African-native species Eumerus obliquus (Fabricius, 1805), which reflect the expansion of this fly through Brazil and Paraguay along the last twenty years. At the same time, we report a second species from Paraguay, Eumerus aurifrons (Wiedemann, 1824), being this the first Western Hemisphere record for this Asian-native species. We finally provide an identification key to all of the species of Eumerus presently known from the Americas and Hawaii.

Palpada panorama sp. n. (Diptera: Syrphidae), a big-eyed hoverfly from Peru and Suriname.

The hoverfly species Palpada panorama sp. n. (Diptera: Syrphidae) is described based on specimens from Peru and Suriname. It belongs to the scutellaris species group and it is most similar to P. erratica (Curran, 1930), from which it differs most notably by the strongly enlarged ommatidia in the upper half of the eye. Additional differences between these two species and an adjustment for the latest identification key for the species of the scutellaris group are given.

Natural history and morphology of the hoverfly Pseudomicrodon biluminiferus and its parasitic relationship with ants nesting in bromeliads.

The syrphid subfamily Microdontinae is characterized by myrmecophily of their immature stages, i.e., they develop in ant nests. Data on natural history of microdontines are scarce, especially in the Neotropics. Based on fieldwork in southern Brazil, this study provided new data on development and ecology of the hoverfly Pseudomicrodon biluminiferus (Hull) (Diptera: Syrphidae) as well as the first morphological descriptions of male genitalia, larvae, and pupa. Immature specimens were specifically found in colonies of the ant species Crematogaster limata Smith (Hymenoptera: Formicidae) found in rosettes of the bromeliad species Aechmea lindenii (E. Morren) Baker (Poales: Bromeliaceae) and A. nudicaulis (L.) Grisebach. Third instar larvae were observed preying on ant larvae, revealing the parasitic nature of P. biluminiferus. In this and several other aspects, the natural history of P. biluminiferus is similar to that of Holarctic microdontine species. Exceptions include: (i) indications that adults of P. biluminiferus outlast the winter months (in contrast to 3(rd)instar larvae in Holarctic species) and (ii) P. biluminiferus' relationship with bromeliads. The importance of bromeliads for this host-parasite system is evaluated in this paper. The single occurrence of another, unidentified microdontine species' pupae in a nest of the ant species Camponotus melanoticus Emery (Hymenoptera: Formicidae) is reported.