Two new bee-killing flies from Brazil (Insecta: Diptera: Phoridae: Melaloncha)

Abstract Background The genus Melaloncha is a large group of species of parasitoid phorid flies that attack Hymenoptera, mostly stingless bees (Meliponinae, Apidae) in the Neotropical Region. New information Two new Brazilian species, Melaloncha (Melaloncha) peacockorum sp. n. and Melaloncha (Udamochiras) nielsi sp. n., are described and their identification clarified.


Introduction
Bee-killing flies of the genus Melaloncha are small (1.5-4.5 mm) fast, agile parasitoids, mostly of stingless bees, bumble bees, and honey bees, but with records also from orchid bees, sweat bees, and vespid wasps (Ament et al. 2013, Brown 2006, Lucia et al. 2013, Lutz and Brown 2013, Ramírez 1982, Wcislo et al. 2004, Brown 2001. Female flies attack hosts by injecting an egg into their body through a membranous area between exoskeleton plates, and the resulting larvae consume and kill them. These flies have been studied in detail recently, with over 150 new species described (Braet 2013, Brown 2004a, Brown 2005, Brown 2006, Brown and Kung 2006, Brown 2004b, Brown 2009, Kung 2008) and phylogenetic relationships hypothesized (Brown andSmith 2010, Smith andBrown 2008). A total of 170 species are now recognized (exclusive of the two described in this paper), but it is likely that many more remain to be found.

Materials and methods
Specimens were borrowed from the collections of the Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil (INPA) and the Universidade de São Paulo, Ribeirão Preto, Brazil. Photographs were taken using a Keyence V5000 digital microscope.

Diagnosis
Dark colored Melaloncha (Melaloncha) with wide, orange, punctate frons, and oviscape with blunt, dorsal, median lobe plus more ventral, bifurcate lobe. In the most recent key to Melaloncha ( Melaloncha) species (Brown 2006), M. peacockorum does not successfully pass couplets 5 to 6, which should be modified as follows:

Distribution
Brazil.

Ecology
Like most Melaloncha species, this fly is probably a parasitoid of stingless bees. It was collected with a Shannon trap, whose operation I have observed in Brazil. The trap is a large structure consisting of a square of black netting, about 3 m in length on each side, with outer walls of the same material. In construction it is like a large box missing the bottom side. The trap is suspended so that the sides are about 0.3 m above the ground, allowing insects access to the bait. Many insects attempt to escape by flying upwards, rather than using the small opening at ground level, and thus get caught in the top of the trap.
The bait used by the researchers is placed in a shallow pit near the center, and consists of a couple of fish, chicken meat, various vegetables, a bag of oatmeal, some mushrooms, human feces, and urine. This smorgasborg "ripens" over several days and attracts hordes of flies, but also other insects including stingless bees, which are frequently attracted to protein (Roubik 1989). Probably, an aggregation of such bees attracted this fly.  Habitus, left lateral, of Melaloncha (Udamochiras) nielsi sp. n.

Diagnosis
Large dark species with oviscape densely setose at base, laterally flattened, dorsal surface curved ventrally. In the key to species (Brown 2004a), M. nielsi comes closest to M. valeria Brown, from which it differs by the dense black setae (absent from M. valeria) and greatly compressed structure of the oviscape. It does not resemble any of the more recently described species of Melaloncha ( Udamochiras) , Brown 2009, Braet 2013).  Oviscape, dorsal, of Melaloncha (Udamochiras) nielsi sp. n.

Etymology
Named for Niels Jensen at the request of Sara Jensen, a supporter of the Entomology Department of the Natural History Museum of Los Angeles County.

Ecology
Unknown, but presumably parasitoids of stingless bees like most other Melaloncha species.