Description of the pupa of Cnemida retusa (Fabricius, 1801) (Melolonthidae: Rutelinae)

Pupae of chafer beetle (Melolonthidae) Cnemida retusa (Fabricius, 1801) (Rutelinae, Rutelini) were collected in October and November of 2017 in a decaying log at Reserva Florestal Adolpho Ducke, Manaus, Amazonas, Brazil, and are described and illustrated. The pupa description is the first to the genus and a key to known pupae of Rutelini is added. Key-Words. Chafers; Neotropical; Scarabaeoidea; White grub.


INTRODUCTION
The Neotropical genus Cnemida Kirby, 1827 (Melolonthidae: Rutelinae: Rutelini) includes 8 species and is identified by the convex body; pronotum longer than wide with a hexagonal shape and posterior margin 3-emargined; robust hind femur; mesepimeron exposed in dorsal view; usually with body color dark and average size of 1 cm (Kirby, 1827;Jameson, 1996).The adults are found on flowers and vegetation (Jameson, 1996).Kirby (1827) related adults covered by "farina" of flowers throughout the cuticular surface, and noted that all species of this genus were collected with some "farinaceous substance" from the plants they frequent, most likely for food.
Regarding genus immatures, the larvae are found in rotting wood feeding on decomposing organic matter (Morón, 1979;Jameson, 1996).Ohaus (1909: 126) reported larvae of C. retusa (Fabricius, 1801) in external parts of rotting wood in "San Antonio de Curaray", close to Curaray River margins, Ecuador, and described the larvae as: cranium reddish brown, slightly shiny and somewhat rugose; mandibles reddish yellow with incisor dark, left incisor 2-toothed, molar long and narrow (0.6 × 0.15 mm); stipes dorsal stridulatory area bearing 9 teeth.In a genus review, Jameson (1996) described other Cnemida larvae, based in larvae of C. intermedia Bates, 1888.Cnemida pupae were unknown until the present work.
Cnemida retusa is the most commonly collected species within the genus, is widely distributed from northern South America to Argentina, and is similar to C. ephippiata Ohaus, 1912and C. tristriata Jameson, 1996(Jameson, 1996).Cnemida retusa is distinguished by the presence of brown or black elytra with orange or bronze spots, elytra with 4 striae and apicomedial elytral margin without strigulae extending up to the lateral disc striations (Jameson, 1996).
The present article purposes to describe the pupae of Cnemida retusa.An identification key to the pupae of Rutelini is also given.

MATERIAL AND METHODS
During two expeditions carried out in the Adolpho Ducke Forest Reserve in Manaus munic-ipality, Amazonas State (AM), in October and November 2017, two adults (one male and one female) and three pupae of Cnemida retusa were found in the sapwood region of a decomposing log.The specimens were taken to the Laboratório de Sistemática e Ecologia de Coleoptera (LASEC) of the Instituto Nacional de Pesquisas da Amazônia (INPA).The pupae were fixed in PAMPEL solution (42% distilled water, 44% alcohol 96° GL, 8% formalin and 5% glacial acetic acid) for 24 hours and then transferred to 80% alcohol.
The adults were identified using the key present in Jameson (1996) and compared with other previously identified specimens deposited in LASEC.The specific attribution of the pupae was performed by the association with adults collected and later identified by observation of diagnoses of teneral adults enclosed in pupal skin.The determination of male and female pupae was possible through the analysis of male and female genital ampulla (cf.Sousa et al., 2018).
Photographs were taken with a Leica DFC295 camera attached to a Leica M165C stereomicroscope and were processed using the Leica Application Suite (LAS) software version 4.1.The photographic illumination system follows Kawada & Buffington (2016).The voucher specimens of this study were deposited in LASEC.