Japanagromyza Sasakawa has currently 80 known species in the world (Lonsdale 2013) and is represented by 30 in the neotropics (Martinez and Etienne 2002, Etienne and Martinez 2003, Sasakawa 2005, Boucher and Hanson 2006, Boucher 2010). Only one species has been recorded from Brazil (São Paulo), Japanagromyza macroptilivora Esposito & Prado (Esposito and Prado 1993). Some species are known to induce galls in plants, 15 of them are associated with plants of the Fabaceae family (Benavent-Corai et al. 2005) and other species are known to induce mines in crop plants (Spencer and Stegmaier 1973).

Japanagromyza is morphologically similar to Agromyza Fallén and Melanagromyza Hendel, although its species can be recognized by the following combination of characters: halter yellow, white, uniformly dark brown or variegated on top or inside of dark knob; thorax with two pairs of dorsocentral setae (rarely three pairs, but anterior ones only a little longer than acrostichals); one pair of scutellar setae (rarely absent); fore tibia with lateral setae in the middle (see Sasakawa 2010 for a complete description of the genus).

Japanagromyza inferna Spencer was originally described from Bahamas, with no information on the host plant (Spencer and Stegmaier 1973). Spencer et al. (1992) reported this species from Guadeloupe, also with no data on the host plant. Years later Etienne and Martinez (2003) recorded from Guadalupe and Saint Christopher, inducing leaf galls on Centrosema virginianum L. (Fabaceae). Centrosema virginianum is found throughout South America in forest scrub, “caatinga” and woodlands (Schultze-Kraft et al. 1990). Other species of Agromyzidae recorded as pests in plants of the genus Centrosema Benth. are Ophiomyia centrosematis (Meijere), Melanagromyza phaseoli Tryon, causing damage and influencing plant growth (Lenné et al. 1990), Japanagromyza centrosematifolii forming mines in Centrosema virginianum and Centrosema pubescens (Etienne and Martinez 2003) and Japanagromyza centrosemae Frost, known on Centrosema pubescens (Spencer 1990).

The main aim of this paper is to present a redescription of Japanagromyza inferna, including characters not yet described, and a key to the 30 Neotropical species of the genus Japanagromyza.

Collections were made bimonthly, from July 2011 to March 2012, in sandbanks in the North coast of the State of Rio de Janeiro (Fig. 1). The localities investigated were Arraial do Cabo, Grussaí (São João da Barra) and Saquarema (coordinates under material examined). In addition to these locations, an extra collection was made in the Marambaia sandbank, also located in Rio de Janeiro (Fig. 1).

To obtain material, branches of the plants with galls were removed and taken to the laboratory. The branches were placed in plastic pots, covered with organza and elastic for rearing and emergence of the adults. After emergence, adults were mounted on entomological pins and were deposited in the collection of Museu Nacional, Universidade Federal do Rio de Janeiro.

The terminalia were clarified in potassium 10% hydroxide for dissection under stereomicroscope and drawn using a camera lucida. Digital images of the gall, pupae and adult were prepared using a Leica MZ 16 optical microscope and the software program AutoMontage Pro by Syncroscopy. The species identification and the key to Neotropical species were based on the original descriptions. The terminology was based on Boucher 2010.